Multiple inheritance completion in Python 2 did not work

Fixes #1071.

jedi/evaluate/arguments.py

@@ -101,7 +101,9 @@ class TreeArguments(AbstractArguments):
         if self.argument_node is None:
             return
 
-        if not (self.argument_node.type == 'arglist' or (
+        # Allow testlist here as well for Python2's class inheritance
+        # definitions.
+        if not (self.argument_node.type in ('arglist', 'testlist') or (
                 # in python 3.5 **arg is an argument, not arglist
                 (self.argument_node.type == 'argument') and
                  self.argument_node.children[0] in ('*', '**'))):

test/completion/classes.py

@@ -215,6 +215,32 @@ class Dude(classgetter()):
         #? ['shout']
         self.s
 
+# -----------------
+# multiple inheritance # 1071
+# -----------------
+
+class FactorMixin(object):
+    FACTOR_1 = 0.1
+
+class Calc(object):
+    def sum(self, a, b):
+        self.xxx = 3
+        return a + b
+
+class BetterCalc(Calc, FactorMixin):
+    def multiply_factor(self, a):
+        return a * self.FACTOR_1
+
+calc = BetterCalc()
+#? ['sum']
+calc.sum
+#? ['multiply_factor']
+calc.multip
+#? ['FACTOR_1']
+calc.FACTOR_1
+#? ['xxx']
+calc.xxx
+
 # -----------------
 # __call__
 # -----------------