code: def set_url(self, url):
          
          # Implemented from template for osid.repository.AssetContentForm.set_url_template
          if self.get_url_metadata().is_read_only():
              raise errors.NoAccess()
          if not self._is_valid_string(
                  url,
                  self.get_url_metadata()):
              raise errors.InvalidArgument()
          self._my_map['url'] = url
docs: Sets the url.
  
          arg:    url (string): the new copyright
          raise:  InvalidArgument - ``url`` is invalid
          raise:  NoAccess - ``Metadata.isReadOnly()`` is ``true``
          raise:  NullArgument - ``url`` is ``null``
          *compliance: mandatory -- This method must be implemented.*