'Returns the angular acceleration Vector of the ReferenceFrame.
Effectively returns the Vector:
^N alpha ^B
which represent the angular acceleration of B in N, where B is self, and
N is otherframe.
Parameters
otherframe : ReferenceFrame
The ReferenceFrame which the angular acceleration is returned in.
Examples
>>> from sympy.physics.vector import ReferenceFrame, Vector
>>> N = ReferenceFrame(\'N\')
>>> A = ReferenceFrame(\'A\')
>>> V = 10 * N.x
>>> A.set_ang_acc(N, V)
>>> A.ang_acc_in(N)
10*N.x'

def ang_acc_in(self, otherframe):

    _check_frame(otherframe)
    if (otherframe in self._ang_acc_dict):
        return self._ang_acc_dict[otherframe]
    else:
        return self.ang_vel_in(otherframe).dt(otherframe)
