def METHOD_NAME(connection):
    """creates basic tx field and site metadata for the mock patients"""
    # the create_mock_patients output is the patient_ident dataframe
    mock_patient_ident_df = mocks.create_mock_patients()
    mock_site_df = mocks.create_mock_treatment_sites(mock_patient_ident_df)
    mock_txfield_df = mocks.create_mock_treatment_fields(mock_site_df)
    mocks.create_mock_treatment_sessions(mock_site_df, mock_txfield_df)
    # sit_set_id = 1 should be a NAL site
    sit_set_id = 1
    # test the get_patient_fields helper function
    sessions_for_one_site = sessions_for_site(connection, sit_set_id)
    sessions_for_one_site = list(sessions_for_one_site)
    print(sessions_for_one_site)
    # make sure the correct number of rows were returned
    assert len(sessions_for_one_site) >= 3
    # for each treatment field
    previous_session_number = None
    previous_session_end = None
    for session_number, session_start, session_end in sessions_for_one_site:
        print(session_number, session_start, session_end)
        if previous_session_number is not None:
            # check that the sessions are in order
            assert session_number > previous_session_number
        if previous_session_end is not None:
            assert session_start > previous_session_end
        assert session_end > session_start
        previous_session_end = session_number
        previous_session_end = session_end