How to use the uncertainties.umath.tan function in uncertainties

beta = par['lam'] - alpha * pi / 180

    # calculate the slope of the center of mass line
    m = -umath.tan(beta)

    # calculate the z intercept
    # this the bicycle frame
    if part == 'B':
        b = -a / umath.cos(beta) - par['rR']
    # this is the fork (without handlebar) or the fork and handlebar combined
    elif part == 'S' or part == 'H':
        b = -a / umath.cos(beta) - par['rF'] + par['w'] * umath.tan(beta)
    # this is the handlebar (without fork)
    elif part == 'G':
        u1, u2 = fwheel_to_handlebar_ref(par['lam'], l1, l2)
        b = -a / umath.cos(beta) - (par['rF'] + u2) + (par['w'] - u1) * umath.tan(beta)
    else:
        print part, "doesn't exist"
        raise KeyError

    return m, b, beta

Parameters
    ----------
    lam : float
        Steer axis tilt.
    l1, l2 : float
        The distance from the front wheel center to the handlebar refernce
        center perpendicular to and along the steer axis.

    Returns
    -------
    u1, u2 : float

    '''

    u1 = l2 * umath.sin(lam) - l1 * umath.cos(lam)
    u2 = u1 / umath.tan(lam) + l1 / umath.sin(lam)
    return u1, u2

Parameters
    ----------
    lam : float
        Steer axis tilt.
    l1, l2 : float
        The distance from the front wheel center to the handlebar refernce
        center perpendicular to and along the steer axis.

    Returns
    -------
    u1, u2 : float

    '''

    u1 = l2 * umath.sin(lam) - l1 * umath.cos(lam)
    u2 = u1 / umath.tan(lam) + l1 / umath.sin(lam)
    return u1, u2

Returns
    -------
    m : float
        The slope of the line in the benchmark coordinate system.
    b : float
        The z intercept in the benchmark coordinate system.

    '''

    # beta is the angle between the x bike frame and the x pendulum frame, rotation
    # about positive y
    beta = par['lam'] - alpha * pi / 180

    # calculate the slope of the center of mass line
    m = -umath.tan(beta)

    # calculate the z intercept
    # this the bicycle frame
    if part == 'B':
        b = -a / umath.cos(beta) - par['rR']
    # this is the fork (without handlebar) or the fork and handlebar combined
    elif part == 'S' or part == 'H':
        b = -a / umath.cos(beta) - par['rF'] + par['w'] * umath.tan(beta)
    # this is the handlebar (without fork)
    elif part == 'G':
        u1, u2 = fwheel_to_handlebar_ref(par['lam'], l1, l2)
        b = -a / umath.cos(beta) - (par['rF'] + u2) + (par['w'] - u1) * umath.tan(beta)
    else:
        print part, "doesn't exist"
        raise KeyError

Returns
    -------
    m : float
        The slope of the line in the benchmark coordinate system.
    b : float
        The z intercept in the benchmark coordinate system.

    '''

    # beta is the angle between the x bike frame and the x pendulum frame, rotation
    # about positive y
    beta = par['lam'] - alpha * pi / 180

    # calculate the slope of the center of mass line
    m = -umath.tan(beta)

    # calculate the z intercept
    # this the bicycle frame
    if part == 'B':
        b = -a / umath.cos(beta) - par['rR']
    # this is the fork (without handlebar) or the fork and handlebar combined
    elif part == 'S' or part == 'H':
        b = -a / umath.cos(beta) - par['rF'] + par['w'] * umath.tan(beta)
    # this is the handlebar (without fork)
    elif part == 'G':
        u1, u2 = fwheel_to_handlebar_ref(par['lam'], l1, l2)
        b = -a / umath.cos(beta) - (par['rF'] + u2) + (par['w'] - u1) * umath.tan(beta)
    else:
        print part, "doesn't exist"
        raise KeyError