<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def kerr_lightring_velocity(chi):
 """Return the velocity at the Kerr light ring"""

    # If chi > 0.9996, the algorithm cannot solve the function
    if chi >= 0.9996:
        return brentq(kerr_lightring, 0, 0.8, args=(0.9996))
    else:
        return brentq(kerr_lightring, 0, 0.8, args=(chi))