Generator for reading from standard input in nonblocking mode.

    Other ways of reading from ``stdin`` in python waits, until the buffer is
    big enough, or until EOF character is sent.

    This functions yields immediately after each line.

def _read_stdin():
    """
    Generator for reading from standard input in nonblocking mode.

    Other ways of reading from ``stdin`` in python waits, until the buffer is
    big enough, or until EOF character is sent.

    This functions yields immediately after each line.
    """
    line = sys.stdin.readline()
    while line:
        yield line
        line = sys.stdin.readline()