    def is_visible(self, x, y):
        """
        Return whether the specified location is on the visible screen.

        :param x: The column (x coord) for the location to check.
        :param y: The line (y coord) for the location to check.
        """
        return ((0 <= x < self.width) and
                (self._start_line <= y < self._start_line + self.height))
Return whether the specified location is on the visible screen.

:param x: The column (x coord) for the location to check.
:param y: The line (y coord) for the location to check.
asciimatics/screen.py