match with python 2.x syntax

ffmpeg/nodes.py

@@ -344,7 +344,7 @@ class MergeOutputsNode(Node):
 
 class HeaderNode (Node):
 
-    def __init__(self, name: str = None, args=[], kwargs={}):
+    def __init__(self, name, args=[], kwargs={}):
         super(HeaderNode, self).__init__(
             stream_spec=None,
             name=name,

ffmpeg/tests/test_facebook.py

@@ -16,7 +16,7 @@ except ImportError:
     from unittest import mock  # python 3
 
 
-def pip_to_rtmp(url: str):
+def pip_to_rtmp(url):
     """ Capture Facetime camera and screen in macOS and stream it to facebook
     """
     facetime_camera_input = (