python中解决You are using pip version 19.2.3, however version 21.0.1 is available.问题

【现象】

D:\data\automatic-watermark-detection-master>python -m pip install estimate_watermark
Collecting estimate_watermark
  ERROR: Could not find a version that satisfies the requirement estimate_watermark (from versions: none)
ERROR: No matching distribution found for estimate_watermark
WARNING: You are using pip version 19.2.3, however version 21.0.1 is available.
You should consider upgrading via the 'python -m pip install --upgrade pip' command.

截图如下：

【解决方法】

D:\data\automatic-watermark-detection-master>python pip install --upgrade pip
python: can't open file 'pip': [Errno 2] No such file or directory

D:\data\automatic-watermark-detection-master>python -m pip install --upgrade pip
Collecting pip
  Downloading https://files.pythonhosted/packages/fe/ef/60d7ba03b5c442309ef42e7d69959f73aacccd0d86008362a681c4698e83/pip-21.0.1-py3-none-any.whl (1.5MB)
     |████████████████████████████████| 1.5MB 61kB/s
Installing collected packages: pip
  Found existing installation: pip 19.2.3
    Uninstalling pip-19.2.3:
      Successfully uninstalled pip-19.2.3
Successfully installed pip-21.0.1

截图如下：