def __init__(self, options, options_class_name, name, full_name,<EOL>file, containing_type, serialized_start=None,<EOL>serialized_end=None):
super(_NestedDescriptorBase, self).__init__(<EOL>options, options_class_name)<EOL>self.name = name<EOL>self.full_name = full_name<EOL>self.file = file<EOL>self.containing_type = containing_type<EOL>self._serialized_start = serialized_start<EOL>self._serialized_end = serialized_end<EOL>
Constructor.

        Args:
          options: Protocol message options or None
            to use default message options.
          options_class_name: (str) The class name of the above options.

          name: (str) Name of this protocol message type.
          full_name: (str) Fully-qualified name of this protocol message type,
            which will include protocol "package" name and the name of any
            enclosing types.
          file: (FileDescriptor) Reference to file info.
          containing_type: if provided, this is a nested descriptor, with this
            descriptor as parent, otherwise None.
          serialized_start: The start index (inclusive) in block in the
            file.serialized_pb that describes this descriptor.
          serialized_end: The end index (exclusive) in block in the
            file.serialized_pb that describes this descriptor.