Allow get_argument_from_call to retrieve the first positional argument.

2 files changed, 5 insertions, 3 deletions

diff --git a/checkers/utils.py b/checkers/utils.py
index 68b5469..5e028f2 100644
--- a/checkers/utils.py
+++ b/checkers/utils.py
@@ -394,10 +394,10 @@ def get_argument_from_call(callfunc_node, position=None, keyword=None):
     :raises NoSuchArgumentError: if no argument at the provided position or with
     the provided keyword.
     """
-    if not position and not keyword:
+    if position is None and keyword is None:
         raise ValueError('Must specify at least one of: position or keyword.')
     try:
-        if position and not isinstance(callfunc_node.args[position], astroid.Keyword):
+        if position is not None and not isinstance(callfunc_node.args[position], astroid.Keyword):
             return callfunc_node.args[position]
     except IndexError as error:
         raise NoSuchArgumentError(error)
diff --git a/test/unittest_checkers_utils.py b/test/unittest_checkers_utils.py
index 683f6b9..f7b0e80 100644
--- a/test/unittest_checkers_utils.py
+++ b/test/unittest_checkers_utils.py
@@ -65,7 +65,9 @@ class UtilsTC(unittest.TestCase):
             utils.get_argument_from_call(node, position=1)
         with self.assertRaises(ValueError):
             utils.get_argument_from_call(node, None, None)
-
+                
+        name = utils.get_argument_from_call(node, position=0)
+        self.assertEqual(name.name, 'a')
 
 if __name__ == '__main__':
     unittest.main()