code: def unescape_unicode(string):
      
      if string is None:
          return string
      # We only want to unescape the unicode, so we first must protect the other
      # backslashes.
      string = string.replace("\\", "\\\\")
      # Now we remove that protection for the unicode.
      string = string.replace("\\\\u", "\\u")
      string = string.replace("\\\\U", "\\U")
      # Now we unescape by evaling the string with the AST. This can't execute
      # code -- it only does the representational level.
      return ast.literal_eval("u'''" + string + "'''")
docs: Python2.7's re module chokes when compiling patterns that have ranges
      between escaped unicode codepoints if the two codepoints are unrecognised
      in the unicode database. For instance:
  
          re.compile('[\\uAA77-\\uAA79]').findall("hello")
  
      Ends up matching every character (on Python 2). This problem doesn't occur
      if we're dealing with unicode literals.