'Get the text of the current source line as a string, with a trailing
newline character'

def current_line(self):

    if self.is_optimized_out():
        return '(frame    information    optimized    out)'
    filename = self.filename()
    with open(os_fsencode(filename), 'r') as f:
        all_lines = f.readlines()
        return all_lines[(self.current_line_num() - 1)]
