Explain another way to install python-gitlab

gl-sak

@@ -44,7 +44,12 @@ except ImportError:
     print("""ERROR: Python GitLab API bindings not found.
 
 Please install 'python-gitlab' and make it available in your Python
-run-time environment.  This recipe should work for most people:
+run-time environment.  One way is to install it system-wide, for
+example like this on Debian GNU/Linux systems:
+
+  $ sudo apt-get install python3-gitlab
+
+Another way is to install it into a local virtual environment:
 
   $ git clone git@gitlab.com:python-gitlab/python-gitlab.git
   $ cd python-gitlab
@@ -53,9 +58,9 @@ run-time environment.  This recipe should work for most people:
   venv$ pip install -e .
   venv$ cd .../wherever/gl-sak/lives
   venv$ ./gl-sak --help
- 
-(See https://python-gitlab.readthedocs.io/en/stable/api-usage.html
-for more about the Python GitLab API package.)""")
+
+See https://python-gitlab.readthedocs.io/en/stable/api-usage.html
+for more about the Python GitLab API package.""")
     sys.exit(1)
 
 # Read https://docs.python.org/dev/library/argparse.html#sub-commands