def clear_score(self):
if self._grade_system.is_based_on_grades():<EOL><INDENT>return  <EOL><DEDENT>if (self.get_score_metadata().is_read_only() or<EOL>self.get_score_metadata().is_required()):<EOL><INDENT>raise errors.NoAccess()<EOL><DEDENT>self._my_map['<STR_LIT>'] = self._score_default<EOL>self._my_map['<STR_LIT>'] = '<STR_LIT>'<EOL>self._my_map['<STR_LIT>'] = None<EOL>
Clears the score.

        raise:  NoAccess - ``Metadata.isRequired()`` or
                ``Metadata.isReadOnly()`` is ``true``
        *compliance: mandatory -- This method must be implemented.*