237 lines
8.1 KiB
Python
237 lines
8.1 KiB
Python
# encoding: utf-8
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"""
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API classes for dealing with presentations and other objects one typically
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encounters as an end-user of the PowerPoint user interface.
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"""
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from __future__ import absolute_import, division, print_function, unicode_literals
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from .opc.constants import RELATIONSHIP_TYPE as RT
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from .opc.package import OpcPackage
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from .opc.packuri import PackURI
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from .parts.coreprops import CorePropertiesPart
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from .parts.image import Image, ImagePart
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from .parts.media import MediaPart
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from .util import lazyproperty
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class Package(OpcPackage):
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"""
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Return an instance of |Package| loaded from *file*, where *file* can be a
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path (a string) or a file-like object. If *file* is a path, it can be
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either a path to a PowerPoint `.pptx` file or a path to a directory
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containing an expanded presentation file, as would result from unzipping
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a `.pptx` file. If *file* is |None|, the default presentation template is
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loaded.
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"""
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@lazyproperty
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def core_properties(self):
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"""
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Instance of |CoreProperties| holding the read/write Dublin Core
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document properties for this presentation. Creates a default core
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properties part if one is not present (not common).
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"""
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try:
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return self.part_related_by(RT.CORE_PROPERTIES)
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except KeyError:
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core_props = CorePropertiesPart.default()
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self.relate_to(core_props, RT.CORE_PROPERTIES)
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return core_props
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def get_or_add_image_part(self, image_file):
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"""
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Return an |ImagePart| object containing the image in *image_file*. If
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the image part already exists in this package, it is reused,
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otherwise a new one is created.
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"""
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return self._image_parts.get_or_add_image_part(image_file)
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def get_or_add_media_part(self, media):
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"""Return a |MediaPart| object containing the media in *media*.
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If a media part for this media bytestream ("file") is already present
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in this package, it is reused, otherwise a new one is created.
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"""
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return self._media_parts.get_or_add_media_part(media)
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def next_image_partname(self, ext):
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"""
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Return a |PackURI| instance representing the next available image
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partname, by sequence number. *ext* is used as the extention on the
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returned partname.
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"""
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def first_available_image_idx():
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image_idxs = sorted(
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[
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part.partname.idx
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for part in self.iter_parts()
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if part.partname.startswith("/ppt/media/image")
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and part.partname.idx is not None
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]
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)
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for i, image_idx in enumerate(image_idxs):
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idx = i + 1
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if idx < image_idx:
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return idx
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return len(image_idxs) + 1
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idx = first_available_image_idx()
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return PackURI("/ppt/media/image%d.%s" % (idx, ext))
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def next_media_partname(self, ext):
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"""Return |PackURI| instance for next available media partname.
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Partname is first available, starting at sequence number 1. Empty
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sequence numbers are reused. *ext* is used as the extension on the
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returned partname.
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"""
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def first_available_media_idx():
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media_idxs = sorted(
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[
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part.partname.idx
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for part in self.iter_parts()
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if part.partname.startswith("/ppt/media/media")
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]
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)
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for i, media_idx in enumerate(media_idxs):
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idx = i + 1
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if idx < media_idx:
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return idx
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return len(media_idxs) + 1
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idx = first_available_media_idx()
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return PackURI("/ppt/media/media%d.%s" % (idx, ext))
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@property
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def presentation_part(self):
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"""
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Reference to the |Presentation| instance contained in this package.
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"""
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return self.main_document_part
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@lazyproperty
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def _image_parts(self):
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"""
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|_ImageParts| object providing access to the image parts in this
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package.
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"""
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return _ImageParts(self)
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@lazyproperty
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def _media_parts(self):
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"""Return |_MediaParts| object for this package.
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The media parts object provides access to all the media parts in this
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package.
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"""
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return _MediaParts(self)
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class _ImageParts(object):
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"""Provides access to the image parts in a package."""
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def __init__(self, package):
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super(_ImageParts, self).__init__()
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self._package = package
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def __iter__(self):
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"""
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Generate a reference to each |ImagePart| object in the package.
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"""
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image_parts = []
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for rel in self._package.iter_rels():
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if rel.is_external:
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continue
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if rel.reltype != RT.IMAGE:
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continue
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image_part = rel.target_part
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if image_part in image_parts:
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continue
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image_parts.append(image_part)
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yield image_part
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def get_or_add_image_part(self, image_file):
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"""
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Return an |ImagePart| object containing the image in *image_file*,
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which is either a path to an image file or a file-like object
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containing an image. If an image part containing this same image
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already exists, that instance is returned, otherwise a new image part
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is created.
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"""
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image = Image.from_file(image_file)
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image_part = self._find_by_sha1(image.sha1)
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if image_part is None:
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image_part = ImagePart.new(self._package, image)
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return image_part
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def _find_by_sha1(self, sha1):
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"""
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Return an |ImagePart| object belonging to this package or |None| if
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no matching image part is found. The image part is identified by the
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SHA1 hash digest of the image binary it contains.
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"""
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for image_part in self:
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# ---skip unknown/unsupported image types, like SVG---
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if not hasattr(image_part, "sha1"):
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continue
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if image_part.sha1 == sha1:
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return image_part
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return None
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class _MediaParts(object):
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"""Provides access to the media parts in a package.
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Supports iteration and :meth:`get()` using the media object SHA1 hash as
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its key.
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"""
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def __init__(self, package):
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super(_MediaParts, self).__init__()
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self._package = package
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def __iter__(self):
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"""Generate a reference to each |MediaPart| object in the package."""
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# A media part can appear in more than one relationship (and commonly
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# does in the case of video). Use media_parts to keep track of those
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# that have been "yielded"; they can be skipped if they occur again.
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media_parts = []
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for rel in self._package.iter_rels():
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if rel.is_external:
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continue
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if rel.reltype not in (RT.MEDIA, RT.VIDEO):
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continue
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media_part = rel.target_part
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if media_part in media_parts:
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continue
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media_parts.append(media_part)
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yield media_part
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def get_or_add_media_part(self, media):
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"""Return a |MediaPart| object containing the media in *media*.
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If this package already contains a media part for the same
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bytestream, that instance is returned, otherwise a new media part is
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created.
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"""
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media_part = self._find_by_sha1(media.sha1)
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if media_part is None:
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media_part = MediaPart.new(self._package, media)
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return media_part
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def _find_by_sha1(self, sha1):
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"""Return |MediaPart| object having *sha1* hash or None if not found.
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All media parts belonging to this package are considered. A media
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part is identified by the SHA1 hash digest of its bytestream
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("file").
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"""
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for media_part in self:
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if media_part.sha1 == sha1:
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return media_part
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return None
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