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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 tri_area(self, lons, lats):
 """ Calculate the area enclosed by 3 points on the unit sphere. Parameters lons : array of floats, shape (3) longitudinal coordinates in radians lats : array of floats, shape (3) latitudinal coordinates in radians Returns ------- area : float area of triangle on the unit sphere """

        lons, lats = self._check_integrity(lons, lats)

        # translate to unit sphere
        x, y, z = _stripack.trans(lats, lons)

        # compute area
        area = _stripack.areas(x, y, z)

        return area