'Parameters
axes_divider : AxesDivider
nx, nx1 : int
Integers specifying the column-position of the
cell. When *nx1* is None, a single *nx*-th column is
specified. Otherwise location of columns spanning between *nx*
to *nx1* (but excluding *nx1*-th column) is specified.
ny, ny1 : int
Same as *nx* and *nx1*, but for row positions.'

def __init__(self, axes_divider, nx, ny, nx1=None, ny1=None):

    self._axes_divider = axes_divider
    _xrefindex = axes_divider._xrefindex
    _yrefindex = axes_divider._yrefindex
    (self._nx, self._ny) = ((nx - _xrefindex), (ny - _yrefindex))
    if (nx1 is None):
        nx1 = (nx + 1)
    if (ny1 is None):
        ny1 = (ny + 1)
    self._nx1 = (nx1 - _xrefindex)
    self._ny1 = (ny1 - _yrefindex)
