print(*values: object,
sep: Optional[Text]=...,
end: Optional[Text]=...,
file: Optional[_Writer]=...,
flush: bool=...) -> None
参数详解：
param *values: object
print(value, ..., sep=' ', end='\n', file=sys.stdout, flush=False)
Prints the values to a stream, or to sys.stdout by default.
Optional keyword arguments:
file: a file-like object (stream); defaults to the current sys.stdout.
sep: string inserted between values, default a space.
end: string appended after the last value, default a newline.
flush: whether to forcibly flush the stream.
print的效用：Prints the values to a stream, or to sys.stdout by default.—将值以流的形式输出，或者使用默认打印在控制台
print函数参数列表：
