def _check_comp(comp):
    """Check that conversion to named matrices is possible."""
    ref_sens = None
    kind = -1
    for k, c_k in enumerate(comp):
        if c_k['coeff_type'] != kind:
            c_ref = c_k
            ref_sens = c_ref['sensors']
            kind = c_k['coeff_type']
        elif not c_k['sensors'] == ref_sens:
            raise RuntimeError('Cannot use an uneven compensation matrix')
