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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _altaz_rotation(self, t):
 """Compute the rotation from the ICRF into the alt-az system."""

        R_lon = rot_z(- self.longitude.radians - t.gast * tau / 24.0)
        return einsum('ij...,jk...,kl...->il...', self.R_lat, R_lon, t.M)