(self, option)
Ensure that 'option' is the name of an existing file.
Ensure that 'option' is the name of an existing file.
Ensure that option is the name of an existing file .
def ensure_filename(self, option):
        """Ensure that 'option' is the name of an existing file."""
        self._ensure_tested_string(option, os.path.isfile,
                                   "filename",
                                   "'%s' does not exist or is not a file")
def ensure_filename ( self , option ) : self . _ensure_tested_string ( option , os . path . isfile , "filename" , "'%s' does not exist or is not a file" )