<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _pid_to_id(self, pid):
 """Converts a pid to a URI that can be used as an OAI-ORE identifier."""

        return d1_common.url.joinPathElements(
            self._base_url,
            self._version_tag,
            "resolve",
            d1_common.url.encodePathElement(pid),
        )