Use any() in the list/tuple branch of occur_check (#1210)

occur_check returns whether var occurs in x; for lists/tuples use any(occur_check(var, e, s) for e in x) - a clean boolean check returning a proper bool - instead of first(...). Applied to logic.py and logic4e.py.

Author: matanw

logic.py

@@ -1766,7 +1766,7 @@ def occur_check(var, x, s):
         return (occur_check(var, x.op, s) or
                 occur_check(var, x.args, s))
     elif isinstance(x, (list, tuple)):
-        return first(e for e in x if occur_check(var, e, s))
+        return any(occur_check(var, e, s) for e in x)
     else:
         return False
 

logic4e.py

@@ -1358,7 +1358,7 @@ def occur_check(var, x, s):
         return (occur_check(var, x.op, s) or
                 occur_check(var, x.args, s))
     elif isinstance(x, (list, tuple)):
-        return first(e for e in x if occur_check(var, e, s))
+        return any(occur_check(var, e, s) for e in x)
     else:
         return False