def unpack_batch_diagnostics(batch_diagnostics):

    """ Unpacks batch diagnostics DataFrame into a python standard dictionary

    Targets old data storage schematic

    Input:
    - batch_diagnostics:                    pandas DataFrame

    Output:
    - unpack_batch_diagnostics:             dict containing simulation runtime diagnostics

    """

    unpack_batch_diagnostics = {}

    for sim_name, sim_diagnostics in batch_diagnostics.items():

        ### unpack simulation diagnostics ###

        # runtime diagnostics
        runtime_diagnostics = sim_diagnostics # the entire pandas df contains runtime diagnostics

        unpacked = [runtime_diagnostics]

        ### end unpack ###

        columns = [
            "runtime_diagnostics"
        ]

        diagnostics = {}
        for (col, diag) in zip(columns, unpacked):
            diagnostics.update({col: diag})

        unpack_batch_diagnostics.update({sim_name: diagnostics})

    return unpack_batch_diagnostics