Get the outer frame coordiantes from a 2D array

outer_coordiantes.py

def outer_coordiantes(arr):
    """
    Get the outer most coordiantes for a 2D array, starting at 0,0.
    >>> outer_coordiantes([[0,0,0],[0,0,0][0,0,0]])
    [(0,0), (0,1), (0,2), (1,2), (2,2), (2,1), (2,0), (1,0)]

    """
    # Top row
    frame_coordiantes = [(0, x) for x in range(len(arr[0]) - 1)]

    # Right row
    frame_coordiantes += [(x, len(arr) - 1) for x in range(len(arr) - 1)]

    # Bottom row
    frame_coordiantes += [
        (len(arr[0]) - 1, x) for x in reversed(range(len(arr[0])))
    ]

    # Left row
    frame_coordiantes += [(x, 0) for x in reversed(range(1, len(arr) - 1))]

    return frame_coordiantes