def handle_occurrence_var(stripped_id, stripped_lvn, stripped_sdc, occurrence_id_compare, occurrence_lvn_compare, occ_index)
      # TODO: Handle specific occurrences of variables that don't self-reference?
      if stripped_id.match(/^#{occurrence_id_compare}/)
        return stripped_id[occ_index]
      elsif stripped_lvn.match(/^#{occurrence_lvn_compare}/)
        return stripped_lvn[occ_index]
      elsif stripped_sdc.match(/^#{occurrence_id_compare}/)
        return stripped_sdc[occ_index]
      end
    end
def handle_occurrence_var(stripped_id, stripped_lvn, stripped_sdc, occurrence_id_compare, occurrence_lvn_compare, occ_index)
      # TODO: Handle specific occurrences of variables that don't self-reference?
      if stripped_id.match(/^#{occurrence_id_compare}/)
        return stripped_id[occ_index]
      elsif stripped_lvn.match(/^#{occurrence_lvn_compare}/)
        return stripped_lvn[occ_index]
      elsif stripped_sdc.match(/^#{occurrence_id_compare}/)
        return stripped_sdc[occ_index]
      end
    end
If the occurrence is a variable, extract the occurrence identifier (if present)