code: def append_inflation_op(self, source=None):
          
          op = operation.Inflation(source)
          return self.append_op(op)
docs: Append a :class:`Inflation
          <stellar_base.operation.Inflation>` operation to the list of
          operations.
  
          :param str source: The source address that is running the inflation
              operation.
          :return: This builder instance.