ERROR: Could not find a version that satisfies the requirement flake8 (from versions: none)
ERROR: No matching distribution found for flake8
Instead of using https://pypi.python.org, we’re using a mirror site, which is:
http://pypi.doubanio.com/simple/
The corresponding command line is

pip install package_name  -i http://pypi.doubanio.com/simple/ --trusted-host pypi.doubanio.com

Read More:

• ERROR: Could not find a version that satisfies the requirement pytest-runner (from versions: none)
• ERROR: Could not find a version that satisfies the requirement absl (from versions: none) ERROR: No
• ERROR: Could not find a version that satisfies the requirement pytube (from versions: none)ERROR: N
• ERROR: Could not find a version that satisfies the requirement tensorfolw==1.14
• python3 (pip3 install threading: ERROR: Cloud not find a version that satisfies the requirement ..)
• [Solved] Could not find a version that satisfies the requirement onnx (from onnx-graphsurgeon0.2.6)
• Using Mocha to test can not find module ‘. /build/release/scrypt’ (Fixed)
• Ambari OpenSSL version problem: sslerror: failed to connect. Please check OpenSSL library versions
• Could NOT find CUDNN: Found unsuitable version “..“, but required is at least “6“
• How to select the jar package version for Maven package when the jar package versions referenced by multiple modules are inconsistent
• Solved! The new version of statsmodels has the problem of importerror: cannot import name ‘factorial’
• This version of chromedriver only supports chrome version 92 crawler simulates the problem of Google plug-in version when the browser clicks and reports an error
• ‘break’ not in the ‘loop’ or ‘switch’ context Error (Fixed)
• Start eclipse and prompt version 1.7.0_ 79 of the JVM is not suitable for this product. Version: 1.8 or greater i…
• Fixed Frame [base_link] does not exist
• Eclipse specifies JDK version to start, and resolves version XXXX of the JVM is not suitable
• error: ‘stoi’ was not declared in this scope linux (Fixed)
• Version 1.8.0_201 of the JVM is not suitable for this product. Version: 11 or greater is required.
• Error: could not find java.dll Error: could not find Java se runtime environment solution
• Eclipse can’t open an error: Error:could not find java SE Runtime Environment/Error: could not find java.dll