<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def xyz2angle(x, y, z):
 """Convert cartesian to azimuth and zenith."""

    azi = xu.rad2deg(xu.arctan2(x, y))
    zen = 90 - xu.rad2deg(xu.arctan2(z, xu.sqrt(x**2 + y**2)))
    return azi, zen