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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _CallMethod(self, srvc, method_descriptor, rpc_controller, request, callback):
 """Calls the method described by a given method descriptor. Args: srvc: Instance of the service for which this method is called. method_descriptor: Descriptor that represent the method to call. rpc_controller: RPC controller to use for this method's execution. request: Request protocol message. callback: A callback to invoke after the method has completed. """

    if method_descriptor.containing_service != self.descriptor:
      raise RuntimeError(
          'CallMethod() given method descriptor for wrong service type.')
    method = getattr(srvc, method_descriptor.name)
    return method(rpc_controller, request, callback)