message: simplify logic as requested in code review
diff: @@ -58,14 +58,11 @@ class TraceableObject(object):
  frame_records = tf_stack.extract_stack()
  if not frame_records:
  return self.FAILURE
  - if len(frame_records) >= local_offset:
  + if len(frame_records) > local_offset:
  # Negative indexing is one-indexed instead of zero-indexed.
  negative_offset = -(local_offset + 1)
  - if len(frame_records) > local_offset:
  self.filename, self.lineno = frame_records[negative_offset][:2]
  return self.SUCCESS
  - else:
  - return self.FAILURE
  else:
  # If the offset is too large then we use the largest offset possible,
  # meaning we use the outermost stack frame at index 0.
  