old_contents: #!python
  # coding=utf-8
  
  
  def cf_safe_name(name):
      import re
      if isinstance(name, str):
          if re.match('^[0-9_]', name):
              # Add a letter to the front
              name = "v_{}".format(name)
          return re.sub(r'[^_a-zA-Z0-9]', "_", name)
  
new_contents: #!python
  # coding=utf-8
  
  
  def isstr(s):
      try:
          return isinstance(s, basestring)
      except NameError:
          return isinstance(s, str)
  
  
  def cf_safe_name(name):
      import re
      if isstr(name):
          if re.match('^[0-9_]', name):
              # Add a letter to the front
              name = "v_{}".format(name)
          return re.sub(r'[^_a-zA-Z0-9]', "_", name)
  
subject: Fix cf_safe_name for python 2.7