'Jump to absolute line offset `line_offset`, load and return it.'

def goto_line(self, line_offset):

    try:
        try:
            self.line_offset = (line_offset - self.input_offset)
            self.line = self.input_lines[self.line_offset]
        except IndexError:
            self.line = None
            raise EOFError
        return self.line
    finally:
        self.notify_observers()
