docs: def clear_completion(self):
          """Clears the completion.
  
          raise:  NoAccess - ``Metadata.isRequired()`` or
                  ``Metadata.isReadOnly()`` is ``true``
          *compliance: mandatory -- This method must be implemented.*
  
          """
          # Implemented from template for osid.grading.GradeSystemForm.clear_lowest_numeric_score
          if (self.get_completion_metadata().is_read_only() or
                  self.get_completion_metadata().is_required()):
              raise errors.NoAccess()
          self._my_map['completion'] = self._completion_default