Do not use assert for functional behavior

assert should not be used for functional code paths.
It can be disabled via Python command line option -O.
In that case __full_version__ would not be set to "unknown".

Use an explicit exception instead.

Author: mbuesch

programmer/tinyprog/__init__.py

@@ -22,8 +22,9 @@
 
 try:
     from .full_version import __full_version__
-    assert __full_version__
-except (ImportError, AssertionError):
+    if not __full_version__:
+        raise ValueError
+except (ImportError, ValueError):
     __full_version__ = "unknown"