docs: def _generate_hash(self):
          """
          Generates a hash based on the specific fields for the method.
          """
          
          self.hash = None
          str_hash = ''
          
          for key, val in self._get_params().iteritems():
              str_hash += smart_str(val)
          
          # Append the encryption string
          str_hash += self._service.encryption_key
          
          # Set md5 hash on the object
          self.hash = hashlib.md5(str_hash).hexdigest()