Added FIXME and Coverage fix.

line.py

@@ -30,6 +30,7 @@ def generate_line(root, node_type):
     int(x, -oo, oo)
     """
 
+    # FIXME: Binding order
     operators = [
             ('+', '-'),
             ('mod', ),
@@ -92,7 +93,7 @@ def generate_line(root, node_type):
                     right = '(' + right + ')'
 
                 s = left + ' ' + s + ' ' + right
-            else:
+            else:  # pragma: nocover
                 raise ValueError('arity = %d is currently not supported.' \
                                  % arity)
         else: