How it works...

In this example, module m1 is specified as a requirement, but the version number doesn't matter; in this case, pip will install the latest version. However, because of the bug in the latest version of m2, an earlier version is specified to be installed. Finally, m3 must be a version between 1.5 and 2.0 to satisfy the installation. Naturally, if one of these conditions can't be met, the installation will fail and the offending library and version numbers will be displayed for further troubleshooting.