How to use the nxviz.polcart.to_cartesian function in nxviz

def test_get_cartesian(r, theta):
    """
    In this test, we are testing to make sure that `get_cartesian` remains a
    wrapper around polcart's `to_cartesian`.
    """
    assume(np.isfinite(theta))
    assume(np.isfinite(r))
    assert get_cartesian(r, theta) == polcart.to_cartesian(r, theta)

def test_convert_rt(r, theta):
    assume(r > 0.01 and r < 1e6)
    assume(np.isfinite(r) and np.isfinite(theta))
    assume(theta <= np.pi and theta >= -np.pi)

    x, y = to_cartesian(r, theta)
    r_new, theta_new = to_polar(x, y)

    assert np.allclose(r, r_new)
    assert np.allclose(abs(theta_new), abs(theta))

def test_convert_xy(x, y):
    assume(x != 0 and y != 0)
    assume(np.isfinite(x) and np.isfinite(y))
    assume(abs(x) < 1e6 and abs(y) < 1e6)
    assume(abs(x) > 0.01 and abs(y) > 0.01)

    # Test radians
    r, theta = to_polar(x, y)
    x_new, y_new = to_cartesian(r, theta)
    assert np.allclose(x, x_new)
    assert np.allclose(y, y_new)

    # Test degrees
    r, theta = to_polar(x, y, theta_units="degrees")
    x_new, y_new = to_cartesian(r, theta, theta_units="degrees")
    assert np.allclose(x, x_new)
    assert np.allclose(y, y_new)

def test_convert_xy(x, y):
    assume(x != 0 and y != 0)
    assume(np.isfinite(x) and np.isfinite(y))
    assume(abs(x) < 1e6 and abs(y) < 1e6)
    assume(abs(x) > 0.01 and abs(y) > 0.01)

    # Test radians
    r, theta = to_polar(x, y)
    x_new, y_new = to_cartesian(r, theta)
    assert np.allclose(x, x_new)
    assert np.allclose(y, y_new)

    # Test degrees
    r, theta = to_polar(x, y, theta_units="degrees")
    x_new, y_new = to_cartesian(r, theta, theta_units="degrees")
    assert np.allclose(x, x_new)
    assert np.allclose(y, y_new)

def get_cartesian(r, theta):
    """
    Returns the cartesian (x,y) coordinates of (r, theta).

    :param r: Real-valued radius.
    :type r: int, float.
    :param theta: Angle
    :type theta: int, float.
    :returns: to_cartesian(r, theta)
    """
    return to_cartesian(r, theta)