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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def ensure_echo_on():
 """Ensure that echo mode is enabled. Some tools such as PDB disable it which causes usability issues after reload."""

    # tcgetattr will fail if stdin isn't a tty
    if not sys.stdin.isatty():
        return
    try:
        import termios
    except ImportError:
        return
    attributes = termios.tcgetattr(sys.stdin)
    if not attributes[3] & termios.ECHO:
        attributes[3] |= termios.ECHO
        termios.tcsetattr(sys.stdin, termios.TCSANOW, attributes)