Function print_warning

Lib/test/support/__init__.py:1500–1506

(msg)

def print_warning(msg):
    # bpo-45410: Explicitly flush stdout to keep logs in order
    flush_std_streams()
    stream = print_warning.orig_stderr
    for line in msg.splitlines():
        print(f"Warning -- {line}", file=stream)
    stream.flush()

# bpo-39983: Store the original sys.stderr at Python startup to be able to
# log warnings even if sys.stderr is captured temporarily by a test.