Snapshot idea/138.1980 from git://git.jetbrains.org/idea/community.git

Change-Id: Ib567c9c152d770212a7a3db20fbf591c210920bd
diff --git a/python/helpers/pydev/pydevd_frame.py b/python/helpers/pydev/pydevd_frame.py
index 374d281..5d1e784 100644
--- a/python/helpers/pydev/pydevd_frame.py
+++ b/python/helpers/pydev/pydevd_frame.py
@@ -15,7 +15,11 @@
     CMD_STEP_INTO, CMD_SMART_STEP_INTO, CMD_RUN_TO_LINE, CMD_SET_NEXT_STATEMENT
 from pydevd_constants import *  # @UnusedWildImport
 from pydevd_file_utils import GetFilenameAndBase
-from pydevd_signature import sendSignatureCallTrace
+try:
+    from pydevd_signature import sendSignatureCallTrace
+except ImportError:
+    def sendSignatureCallTrace(*args, **kwargs):
+        pass
 import pydevd_vars
 import pydevd_dont_trace