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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 get_angle(self, i: int, j: int, k: int) -> float: """ Returns angle specified by three sites. Args: i: Index of first site. j: Index of second site. k: Index of third site. Returns: Angle in degrees. """

        v1 = self[i].coords - self[j].coords
        v2 = self[k].coords - self[j].coords
        return get_angle(v1, v2, units="degrees")