def pivotCombinedInventories(combinedinventory_df):
    """Create a pivot table of combined emissions.

    :param combinedinventory_df: pandas dataframe returned from a
        'combineInventories..' function
    :return: pandas pivot_table
    """
    # Group the results by facility,flow,and compartment
    combinedinventory_df_pt = combinedinventory_df.pivot_table(
        values=['FlowAmount', 'DataReliability'],
        index=['FRS_ID', 'SRS_ID', 'Compartment'],
        columns='Source')
    return combinedinventory_df_pt