Update newrelic/core/node_mixin.py

Author: hmstepanek

newrelic/core/node_mixin.py

@@ -52,7 +52,7 @@ def get_trace_segment_params(self, settings, params=None):
         _params["exclusive_duration_millis"] = 1000.0 * self.exclusive
         return _params
 
-    def span_event(self, settings, base_attrs=None, parent_guid=None, attr_class=dict, ct_exit_spans=None, ct_processing_time=0):
+    def span_event(self, settings, base_attrs=None, parent_guid=None, attr_class=dict, ct_exit_spans=None, ct_processing_time=None):
         if ct_exit_spans is None:
             ct_exit_spans = {}
         i_attrs = base_attrs and base_attrs.copy() or attr_class()