Construct a reshaped-array for corsen

def _coarsen_reshape(self, windows, boundary, side):
        """
        Construct a reshaped-array for corsen
        """
        if not utils.is_dict_like(boundary):
            boundary = {d: boundary for d in windows.keys()}

        if not utils.is_dict_like(side):
            side = {d: side for d in windows.keys()}

        # remove unrelated dimensions
        boundary = {k: v for k, v in boundary.items() if k in windows}
        side = {k: v for k, v in side.items() if k in windows}

        for d, window in windows.items():
            if window <= 0:
                raise ValueError('window must be > 0. Given {}'.format(window))

        variable = self
        for d, window in windows.items():
            # trim or pad the object
            size = variable.shape[self._get_axis_num(d)]
            n = int(size / window)
            if boundary[d] == 'exact':
                if n * window != size:
                    raise ValueError(
                        'Could not coarsen a dimension of size {} with '
                        'window {}'.format(size, window))
            elif boundary[d] == 'trim':
                if side[d] == 'left':
                    variable = variable.isel({d: slice(0, window * n)})
                else:
                    excess = size - window * n
                    variable = variable.isel({d: slice(excess, None)})
            elif boundary[d] == 'pad':  # pad
                pad = window * n - size
                if pad < 0:
                    pad += window
                if side[d] == 'left':
                    pad_widths = {d: (0, pad)}
                else:
                    pad_widths = {d: (pad, 0)}
                variable = variable.pad_with_fill_value(pad_widths)
            else:
                raise TypeError(
                    "{} is invalid for boundary. Valid option is 'exact', "
                    "'trim' and 'pad'".format(boundary[d]))

        shape = []
        axes = []
        axis_count = 0
        for i, d in enumerate(variable.dims):
            if d in windows:
                size = variable.shape[i]
                shape.append(int(size / windows[d]))
                shape.append(windows[d])
                axis_count += 1
                axes.append(i + axis_count)
            else:
                shape.append(variable.shape[i])

        return variable.data.reshape(shape), tuple(axes)