Came across this when deploying a Django app to a fresh VM, installing with Python PIP from a requirements file.
pip install -r requirements.txt
>>> Cannot find command 'svn'
The line in question was
I thought the error was that I had an old version of PIP which didn’t support the svn syntax.
Turns out subversion wasn’t installed on the system and it was literally the `svn` shell command (i.e. Subversion client executable) that couldn’t be found. Simple.