def _check_radians(value, max_radians=2 * np.pi):
    """Input validation of values that could be in degrees instead of radians.

    Parameters
    ----------
    value : `pint.Quantity`
        The input value to check.

    max_radians : float
        Maximum absolute value of radians before warning.

    Returns
    -------
    `pint.Quantity`
        The input value

    """
    try:
        value = value.to('radians').m
    except AttributeError:
        pass
    if np.greater(np.nanmax(np.abs(value)), max_radians):
        warnings.warn('Input over {} radians. '
                      'Ensure proper units are given.'.format(max_radians))
    return value