def set_url(self, url=None):
if url is None:<EOL><INDENT>raise NullArgument()<EOL><DEDENT>metadata = Metadata(**settings.METADATA['<STR_LIT:url>'])<EOL>if metadata.is_read_only():<EOL><INDENT>raise NoAccess()<EOL><DEDENT>if self._is_valid_input(url, metadata, array=False):<EOL><INDENT>self._my_map['<STR_LIT:url>'] = url<EOL><DEDENT>else:<EOL><INDENT>raise InvalidArgument()<EOL><DEDENT>
Sets the url.

        :param url: the new copyright
        :type url: ``string``
        :raise: ``InvalidArgument`` -- ``url`` is invalid
        :raise: ``NoAccess`` -- ``Metadata.isReadOnly()`` is ``true``
        :raise: ``NullArgument`` -- ``url`` is ``null``

        *compliance: mandatory -- This method must be implemented.*