<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _build_wells(self) -> List[Well]: """ This function is used to create one instance of wells to be used by all accessor functions. It is only called again if a new offset needs to be applied. """

        return [
            Well(
                self._well_definition[well],
                Location(self._calibrated_offset, self),
                "{} of {}".format(well, self._display_name),
                self.is_tiprack)
            for well in self._ordering]