(self, message_descriptor, number)
return self._extensions_by_number[message_descriptor][number]
Gets the extension of the specified message with the specified number.

    Extensions have to be registered to this pool by calling
    AddExtensionDescriptor.

    Args:
      message_descriptor: descriptor of the extended message.
      number: integer, number of the extension field.

    Returns:
      A FieldDescriptor describing the extension.

    Raise:
      KeyError: when no extension with the given number is known for the
        specified message.
Gets the extension of the specified message with the specified number.
Gets the extension of the specified message with the specified number .
def FindExtensionByNumber(self, message_descriptor, number):
    """Gets the extension of the specified message with the specified number.

    Extensions have to be registered to this pool by calling
    AddExtensionDescriptor.

    Args:
      message_descriptor: descriptor of the extended message.
      number: integer, number of the extension field.

    Returns:
      A FieldDescriptor describing the extension.

    Raise:
      KeyError: when no extension with the given number is known for the
        specified message.
    """
    return self._extensions_by_number[message_descriptor][number]
def FindExtensionByNumber ( self , message_descriptor , number ) : return self . _extensions_by_number [ message_descriptor ] [ number ]