code: def GetMessages(self, files):
      
  
      result = {}
      for f in files:
        result.update(self._symbols_by_file[f])
      return result
docs: Gets all the messages from a specified file.
  
      This will find and resolve dependencies, failing if they are not registered
      in the symbol database.
  
  
      Args:
        files: The file names to extract messages from.
  
      Returns:
        A dictionary mapping proto names to the message classes. This will include
        any dependent messages as well as any messages defined in the same file as
        a specified message.
  
      Raises:
        KeyError: if a file could not be found.