code: def is_named(self, filename):
          
          self.is_file()
          if not isinstance(filename, str_types):
              raise TypeError('given filename arg must be a path')
          val_filename = os.path.basename(os.path.abspath(self.val))
          if val_filename != filename:
              self._err('Expected filename <%s> to be equal to <%s>, but was not.' % (val_filename, filename))
          return self
docs: Asserts that val is an existing path to a file and that file is named filename.