def __new__(cls, arr, mask, *args, **kwargs):
obj = arr.view(cls)<EOL>obj.mask = mask<EOL>obj.interpolator = None<EOL>return obj<EOL>
A regular grid of coordinates, where each entry corresponds to the (y,x) coordinates at the centre of an \
        unmasked pixel. The positive y-axis is upwards and poitive x-axis to the right. 

        A *RegularGrid* is ordered such pixels begin from the top-row of the mask and go rightwards and then \ 
        downwards. Therefore, it is a ndarray of shape [total_unmasked_pixels, 2]. The first element of the ndarray \
        thus corresponds to the regular pixel index and second element the y or x arc -econd coordinates. For example:

        - regular_grid[3,0] = the 4th unmasked pixel's y-coordinate.
        - regular_grid[6,1] = the 7th unmasked pixel's x-coordinate.

        Below is a visual illustration of a regular-grid, where a total of 10 pixels are unmasked and are included in \
        the grid.

        |x|x|x|x|x|x|x|x|x|x|
        |x|x|x|x|x|x|x|x|x|x|     This is an example mask.Mask, where:
        |x|x|x|x|x|x|x|x|x|x|
        |x|x|x|x|o|o|x|x|x|x|     x = True (Pixel is masked and excluded from the regular grid)
        |x|x|x|o|o|o|o|x|x|x|     o = False (Pixel is not masked and included in the regular grid)
        |x|x|x|o|o|o|o|x|x|x|
        |x|x|x|x|x|x|x|x|x|x|
        |x|x|x|x|x|x|x|x|x|x|
        |x|x|x|x|x|x|x|x|x|x|
        |x|x|x|x|x|x|x|x|x|x|

        The mask pixel index's will come out like this (and the direction of arc-second coordinates is highlighted
        around the mask.

        pixel_scale = 1.0"

        <--- -ve  x  +ve -->
                                                        y      x
        |x|x|x|x|x|x|x|x|x|x|  ^   regular_grid[0] = [ 1.5, -0.5]
        |x|x|x|x|x|x|x|x|x|x|  |   regular_grid[1] = [ 1.5,  0.5]
        |x|x|x|x|x|x|x|x|x|x|  |   regular_grid[2] = [ 0.5, -1.5]
        |x|x|x|x|0|1|x|x|x|x| +ve  regular_grid[3] = [ 0.5, -0.5]
        |x|x|x|2|3|4|5|x|x|x|  y   regular_grid[4] = [ 0.5,  0.5]
        |x|x|x|6|7|8|9|x|x|x| -ve  regular_grid[5] = [ 0.5,  1.5]
        |x|x|x|x|x|x|x|x|x|x|  |   regular_grid[6] = [-0.5, -1.5]
        |x|x|x|x|x|x|x|x|x|x|  |   regular_grid[7] = [-0.5, -0.5]
        |x|x|x|x|x|x|x|x|x|x| \/   regular_grid[8] = [-0.5,  0.5]
        |x|x|x|x|x|x|x|x|x|x|      regular_grid[9] = [-0.5,  1.5]