check_params: check whether some parameters are missing

def check_params(**kwargs):
    """check_params: check whether some parameters are missing
    """

    missing_params = []
    check = True

    for param in kwargs:
        if kwargs[param] is None:
            missing_params.append(param)

    if len(missing_params) > 0:
        print("POT - Warning: following necessary parameters are missing")
        for p in missing_params:
            print("\n", p)

        check = False

    return check