ryu installtion failure

[Komori-Chiyu]

I was trying to install ryu using the line"mininet@mininet-vm:~$ pip install -r CS305-2023Spring-Project/requirements.txt -i https://pypi.tuna.tsinghua.edu.cn/simple ", and I get the error message below:
Complete output from command python setup.py egg_info:
Traceback (most recent call last):
File "", line 1, in
File "/tmp/pip-build-XU3C1m/ovs/setup.py", line 28
file=sys.stderr)
^
SyntaxError: invalid syntax

----------------------------------------

Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-XU3C1m/ovs/