'Set a screen on this Pipeline.
Parameters
filter : zipline.pipeline.Filter
The filter to apply as a screen.
overwrite : bool
Whether to overwrite any existing screen.  If overwrite is False
and self.screen is not None, we raise an error.'

@expect_types(screen=Filter, overwrite=(bool, int))
def set_screen(self, screen, overwrite=False):

    if ((self._screen is not None) and (not overwrite)):
        raise ValueError('set_screen()    called    with    overwrite=False    and    screen    already    set.\nIf    you    want    to    apply    multiple    filters    as    a    screen    use    set_screen(filter1    &    filter2    &    ...).\nIf    you    want    to    replace    the    previous    screen    with    a    new    one,    use    set_screen(new_filter,    overwrite=True).')
    self._screen = screen
