def are_not_nat(builder, vals):
    """
    Return a predicate which is true if all of *vals* are not NaT.
    """
    assert len(vals) >= 1
    pred = is_not_nat(builder, vals[0])
    for val in vals[1:]:
        pred = builder.and_(pred, is_not_nat(builder, val))
    return pred

    Return a predicate which is true if all of *vals* are not NaT.
    
numba/np/npdatetime.py