message: don't generate double underscores in method names
diff: @@ -911,7 +911,7 @@ $code
  #
  def camel_case_to_snake_case(name):
  - res = re.sub('(.)([A-Z][a-z]+)', r'\1_\2', name)
  + res = re.sub('([^_])([A-Z][a-z]+)', r'\1_\2', name)
  res = re.sub('([a-z0-9])([A-Z])', r'\1_\2', res)
  res = re.sub(r'\B([23])_(D)\b', r'_\1\2', res) # fix 2_d and 3_d
  return res.lower()
  