Error: option — single version externally managed not recognized

When PIP install mysql-connector-Python-RF ==2.1.3, the MAC receives an error message:
error: option –single-version-externally-managed not recognized

The reason may be that your installation package is in wheel format. If you do not have wheels installed on your computer, you will report this error.
Here’s how I solved it:
First install the wheel: PIP Install wheel
Then PIP install the package I want: PIP install mysql-connector-Python-RF ==2.1.3
Solved my problem:

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