Because the documentation says so
print(*objects, sep=' ', end='\n', file=sys.stdout, flush=False)
Print objects to the text stream file, separated by sep and followed by end. sep, end and file, if present, must be given as keyword arguments.
All non-keyword arguments are converted to strings like str() does and written to the stream, separated by sep and followed by end. Both sep and end must be strings; they can also be None, which means to use the default values. If no objects are given,
print()will just write
The file argument must be an object with a write(string) method; if it is not present or None, sys.stdout will be used. Since printed arguments are converted to text strings, print() cannot be used with binary mode file objects. For these, use file.write(...) instead.
Whether output is buffered is usually determined by file, but if the flush keyword argument is true, the stream is forcibly flushed.
Changed in version 3.3: Added the flush keyword argument.
end is defaulted to
'\n' which is a new line.