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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_dihedral(self, i: int, j: int, k: int, l: int) -> float: """ Returns dihedral angle specified by four sites. Args: i: Index of first site j: Index of second site k: Index of third site l: Index of fourth site Returns: Dihedral angle in degrees. """

        v1 = self[k].coords - self[l].coords
        v2 = self[j].coords - self[k].coords
        v3 = self[i].coords - self[j].coords
        v23 = np.cross(v2, v3)
        v12 = np.cross(v1, v2)
        return math.degrees(math.atan2(np.linalg.norm(v2) * np.dot(v1, v23),
                                       np.dot(v12, v23)))