def get_measured_by_datatype(data):
    """ Get unique list of species for each 'source' label in data.

    Parameters
    ----------
    data : ExperimentalData

    Returns
    -------
    measured, sig_measured : dict, dict
        Dictionaries where keys are 'source' and values are sets of ids.

    """

    measured = dict()
    sig_measured = dict()
    for i in data.exp_methods:
        sig_measured[i] = set(data[i].sig.id_list)
        measured[i] = set(data[i].id_list)
    return measured, sig_measured