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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 _calc_coordinates(self):
 """ Calculate the coordinates to use when calling an interpolator. These are needed for `Background2D` and `BackgroundIDW2D`. Regular-grid interpolators require a 2D array of values. Some require a 2D meshgrid of x and y. Other require a strictly increasing 1D array of the x and y ranges. """


        # the position coordinates used to initialize an interpolation
        self.y = (self.mesh_yidx * self.box_size[0] +
                  (self.box_size[0] - 1) / 2.)
        self.x = (self.mesh_xidx * self.box_size[1] +
                  (self.box_size[1] - 1) / 2.)
        self.yx = np.column_stack([self.y, self.x])

        # the position coordinates used when calling an interpolator
        nx, ny = self.data.shape
        self.data_coords = np.array(list(product(range(ny), range(nx))))