code: def set_timestamp(self, timestamp):
          
          # Implemented from template for osid.assessment.AssessmentOfferedForm.set_start_time_template
          if self.get_timestamp_metadata().is_read_only():
              raise errors.NoAccess()
          if not self._is_valid_date_time(
                  timestamp,
                  self.get_timestamp_metadata()):
              raise errors.InvalidArgument()
          self._my_map['timestamp'] = timestamp
docs: Sets the timestamp.
  
          arg:    timestamp (osid.calendaring.DateTime): the new timestamp
          raise:  InvalidArgument - ``timestamp`` is invalid
          raise:  NoAccess - ``Metadata.isReadOnly()`` is ``true``
          raise:  NullArgument - ``timestamp`` is ``null``
          *compliance: mandatory -- This method must be implemented.*