code: def _formatEvidence(self, elements):
          
          elementClause = None
          filters = []
          for evidence in elements:
              if evidence.description:
                  elementClause = 'regex(?{}, "{}")'.format(
                      'environment_label', evidence.description)
              if (hasattr(evidence, 'externalIdentifiers') and
                      evidence.externalIdentifiers):
                  # TODO will this pick up > 1 externalIdentifiers ?
                  for externalIdentifier in evidence['externalIdentifiers']:
                      exid_clause = self._formatExternalIdentifier(
                          externalIdentifier, 'environment')
                      # cleanup parens from _formatExternalIdentifier method
                      elementClause = exid_clause[1:-1]
              if elementClause:
                  filters.append(elementClause)
          elementClause = "({})".format(" || ".join(filters))
          return elementClause
docs: Formats elements passed into parts of a query for filtering