add reference number generator

DialoguePolicy.py

@@ -1,11 +1,18 @@
 from collections import defaultdict
 import json
+import random
+import string
 from copy import deepcopy
 from convlab.policy.policy import Policy
 
 db_path = './hotels_data.json'
 
 
+def generate_reference_number(length=8):
+    letters_and_digits = string.ascii_uppercase + string.digits
+    reference_number = ''.join(random.choice(letters_and_digits) for _ in range(length))
+    return reference_number
+
 class DialoguePolicy(Policy):
     info_dict = None
     def __init__(self):
@@ -41,7 +48,8 @@ class DialoguePolicy(Policy):
         if any(True for slots in user_action.values() for (slot, _) in slots if
                slot in ['book stay', 'book day', 'book people']):
             if self.results:
-                system_action = {('Booking', 'Book'): [["Ref", self.results[0].get('Ref', 'N/A')]]}
+                reference_number = generate_reference_number()
+                system_action = {('Booking', 'Book'): [["Ref", reference_number]]}
 
         system_acts = [[intent, domain, slot, value] for (domain, intent), slots in system_action.items() for
                        slot, value in slots]