248 lines
6.6 KiB
Python
248 lines
6.6 KiB
Python
"""
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Python 3 compatibility tools.
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"""
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from __future__ import division, absolute_import, print_function
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__all__ = ['bytes', 'asbytes', 'isfileobj', 'getexception', 'strchar',
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'unicode', 'asunicode', 'asbytes_nested', 'asunicode_nested',
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'asstr', 'open_latin1', 'long', 'basestring', 'sixu',
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'integer_types', 'is_pathlib_path', 'npy_load_module', 'Path',
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'pickle', 'contextlib_nullcontext', 'os_fspath', 'os_PathLike']
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import sys
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import os
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try:
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from pathlib import Path, PurePath
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except ImportError:
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Path = PurePath = None
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if sys.version_info[0] >= 3:
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import io
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try:
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import pickle5 as pickle
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except ImportError:
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import pickle
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long = int
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integer_types = (int,)
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basestring = str
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unicode = str
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bytes = bytes
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def asunicode(s):
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if isinstance(s, bytes):
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return s.decode('latin1')
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return str(s)
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def asbytes(s):
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if isinstance(s, bytes):
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return s
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return str(s).encode('latin1')
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def asstr(s):
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if isinstance(s, bytes):
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return s.decode('latin1')
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return str(s)
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def isfileobj(f):
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return isinstance(f, (io.FileIO, io.BufferedReader, io.BufferedWriter))
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def open_latin1(filename, mode='r'):
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return open(filename, mode=mode, encoding='iso-8859-1')
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def sixu(s):
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return s
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strchar = 'U'
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else:
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import cpickle as pickle
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bytes = str
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long = long
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basestring = basestring
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unicode = unicode
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integer_types = (int, long)
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asbytes = str
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asstr = str
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strchar = 'S'
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def isfileobj(f):
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return isinstance(f, file)
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def asunicode(s):
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if isinstance(s, unicode):
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return s
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return str(s).decode('ascii')
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def open_latin1(filename, mode='r'):
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return open(filename, mode=mode)
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def sixu(s):
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return unicode(s, 'unicode_escape')
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def getexception():
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return sys.exc_info()[1]
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def asbytes_nested(x):
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if hasattr(x, '__iter__') and not isinstance(x, (bytes, unicode)):
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return [asbytes_nested(y) for y in x]
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else:
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return asbytes(x)
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def asunicode_nested(x):
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if hasattr(x, '__iter__') and not isinstance(x, (bytes, unicode)):
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return [asunicode_nested(y) for y in x]
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else:
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return asunicode(x)
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def is_pathlib_path(obj):
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"""
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Check whether obj is a pathlib.Path object.
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Prefer using `isinstance(obj, os_PathLike)` instead of this function.
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"""
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return Path is not None and isinstance(obj, Path)
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# from Python 3.7
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class contextlib_nullcontext(object):
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"""Context manager that does no additional processing.
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Used as a stand-in for a normal context manager, when a particular
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block of code is only sometimes used with a normal context manager:
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cm = optional_cm if condition else nullcontext()
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with cm:
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# Perform operation, using optional_cm if condition is True
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"""
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def __init__(self, enter_result=None):
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self.enter_result = enter_result
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def __enter__(self):
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return self.enter_result
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def __exit__(self, *excinfo):
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pass
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if sys.version_info[0] >= 3 and sys.version_info[1] >= 4:
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def npy_load_module(name, fn, info=None):
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"""
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Load a module.
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.. versionadded:: 1.11.2
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Parameters
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----------
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name : str
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Full module name.
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fn : str
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Path to module file.
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info : tuple, optional
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Only here for backward compatibility with Python 2.*.
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Returns
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-------
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mod : module
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"""
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import importlib.machinery
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return importlib.machinery.SourceFileLoader(name, fn).load_module()
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else:
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def npy_load_module(name, fn, info=None):
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"""
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Load a module.
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.. versionadded:: 1.11.2
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Parameters
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----------
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name : str
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Full module name.
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fn : str
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Path to module file.
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info : tuple, optional
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Information as returned by `imp.find_module`
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(suffix, mode, type).
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Returns
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-------
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mod : module
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"""
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import imp
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if info is None:
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path = os.path.dirname(fn)
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fo, fn, info = imp.find_module(name, [path])
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else:
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fo = open(fn, info[1])
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try:
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mod = imp.load_module(name, fo, fn, info)
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finally:
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fo.close()
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return mod
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# backport abc.ABC
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import abc
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if sys.version_info[:2] >= (3, 4):
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abc_ABC = abc.ABC
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else:
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abc_ABC = abc.ABCMeta('ABC', (object,), {'__slots__': ()})
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# Backport os.fs_path, os.PathLike, and PurePath.__fspath__
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if sys.version_info[:2] >= (3, 6):
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os_fspath = os.fspath
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os_PathLike = os.PathLike
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else:
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def _PurePath__fspath__(self):
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return str(self)
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class os_PathLike(abc_ABC):
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"""Abstract base class for implementing the file system path protocol."""
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@abc.abstractmethod
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def __fspath__(self):
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"""Return the file system path representation of the object."""
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raise NotImplementedError
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@classmethod
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def __subclasshook__(cls, subclass):
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if PurePath is not None and issubclass(subclass, PurePath):
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return True
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return hasattr(subclass, '__fspath__')
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def os_fspath(path):
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"""Return the path representation of a path-like object.
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If str or bytes is passed in, it is returned unchanged. Otherwise the
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os.PathLike interface is used to get the path representation. If the
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path representation is not str or bytes, TypeError is raised. If the
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provided path is not str, bytes, or os.PathLike, TypeError is raised.
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"""
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if isinstance(path, (str, bytes)):
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return path
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# Work from the object's type to match method resolution of other magic
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# methods.
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path_type = type(path)
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try:
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path_repr = path_type.__fspath__(path)
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except AttributeError:
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if hasattr(path_type, '__fspath__'):
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raise
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elif PurePath is not None and issubclass(path_type, PurePath):
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return _PurePath__fspath__(path)
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else:
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raise TypeError("expected str, bytes or os.PathLike object, "
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"not " + path_type.__name__)
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if isinstance(path_repr, (str, bytes)):
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return path_repr
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else:
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raise TypeError("expected {}.__fspath__() to return str or bytes, "
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"not {}".format(path_type.__name__,
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type(path_repr).__name__))
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