Make symbolnames return a tuple

diff --git a/pypol/linexprs.py b/pypol/linexprs.py
index b330045..10daf9d 100644 (file)
--- a/pypol/linexprs.py
+++ b/pypol/linexprs.py
@@ -441,7 +441,7 @@ def symbolname(symbol):
 def symbolnames(symbols):
     if isinstance(symbols, str):
         return symbols.replace(',', ' ').split()
-    return (symbolname(symbol) for symbol in symbols)
+    return tuple(symbolname(symbol) for symbol in symbols)
 
 
 class Constant(Expression):