We have the acos function, which returns the angle in radians.
>>> import math
>>> math.acos(0)
1.5707963267948966
>>> _ * 2 - math.pi
0.0
We have the acos function, which returns the angle in radians.
>>> import math
>>> math.acos(0)
1.5707963267948966
>>> _ * 2 - math.pi
0.0