code: def get_encoding_name(self, encoding):
          
          encoding = CodePages.get_encoding_name(encoding)
          if encoding not in self.codepages:
              raise ValueError((
                  'Encoding "{}" cannot be used for the current profile. '
                  'Valid encodings are: {}'
                  ).format(encoding, ','.join(self.codepages.keys())))
          return encoding
docs: Given an encoding provided by the user, will return a
          canonical encoding name; and also validate that the encoding
          is supported.
  
          TODO: Support encoding aliases: pc437 instead of cp437.