parameters: (field)
return_statement: return (field.is_extension and
            field.containing_type.has_options and
            field.containing_type.GetOptions().message_set_wire_format and
            field.type == _TYPE_MESSAGE and
            field.message_type == field.extension_scope and
            field.label == _LABEL_OPTIONAL)
docstring: Checks if a field is a message set extension.
docstring_summary: Checks if a field is a message set extension.
docstring_tokens: Checks if a field is a message set extension .
function: def _IsMessageSetExtension(field):
    """Checks if a field is a message set extension."""
    return (field.is_extension and
            field.containing_type.has_options and
            field.containing_type.GetOptions().message_set_wire_format and
            field.type == _TYPE_MESSAGE and
            field.message_type == field.extension_scope and
            field.label == _LABEL_OPTIONAL)
function_tokens: def _IsMessageSetExtension ( field ) : return ( field . is_extension and field . containing_type . has_options and field . containing_type . GetOptions ( ) . message_set_wire_format and field . type == _TYPE_MESSAGE and field . message_type == field . extension_scope and field . label == _LABEL_OPTIONAL )