def FindServiceByName(self, full_name):
    """Loads the named service descriptor from the pool.

    Args:
      full_name (str): The full name of the service descriptor to load.

    Returns:
      ServiceDescriptor: The service descriptor for the named service.

    Raises:
      KeyError: if the service cannot be found in the pool.
    """
    full_name = _NormalizeFullyQualifiedName(full_name)
    if full_name not in self._service_descriptors:
      self._FindFileContainingSymbolInDb(full_name)
    return self._service_descriptors[full_name]
Loads the named service descriptor from the pool.

    Args:
      full_name (str): The full name of the service descriptor to load.

    Returns:
      ServiceDescriptor: The service descriptor for the named service.

    Raises:
      KeyError: if the service cannot be found in the pool.
    
deps/protobuf/python/google/protobuf/descriptor_pool.py