def METHOD_NAME(self, stash, x_coord, y_coord):
    self.ff2pp._custom_stash = stash
    field = next(iter(self.ff2pp))
    self.assertArrayEqual(
        x_coord,
        field.x,
        ("x_coord was incorrect for " "stash {}".format(stash)),
    )
    self.assertArrayEqual(
        y_coord,
        field.y,
        ("y_coord was incorrect for " "stash {}".format(stash)),
    )