code: def _construct_new_key(name, units=None):
      
      to_replace = ["/", "\\", "*", "^", "#", " ", "\n", "\t", ",", ".", ")", "(", "'", "`", "-"]
      to_remove = ["$", "{", "}"]
  
      cat = name
      if units:
          cat = "_".join([name, units])
      for c in to_replace:
         cat = cat.replace(c, "_")
      for c in to_remove:
         cat = cat.replace(c, "")
  
      cat = re.sub('_+','_', cat)
  
      return cat
docs: Construct an MDF safe key from the name and units