Converts a generator with approval rows into ApprovalRequest objects.

def _ResponseToApprovalsWithGrants(response):
  """Converts a generator with approval rows into ApprovalRequest objects."""
  prev_triplet = None
  cur_approval_request = None
  for (approval_id_int, approval_timestamp, approval_request_bytes,
       grantor_username, grant_timestamp) in response:

    cur_triplet = (approval_id_int, approval_timestamp, approval_request_bytes)

    if cur_triplet != prev_triplet:
      prev_triplet = cur_triplet

      if cur_approval_request:
        yield cur_approval_request

      cur_approval_request = mysql_utils.StringToRDFProto(
          rdf_objects.ApprovalRequest, approval_request_bytes)
      cur_approval_request.approval_id = _IntToApprovalID(approval_id_int)
      cur_approval_request.timestamp = mysql_utils.TimestampToRDFDatetime(
          approval_timestamp)

    if grantor_username and grant_timestamp:
      cur_approval_request.grants.append(
          rdf_objects.ApprovalGrant(
              grantor_username=grantor_username,
              timestamp=mysql_utils.TimestampToRDFDatetime(grant_timestamp)))

  if cur_approval_request:
    yield cur_approval_request