Appends the given content to the file. Existing content is
        preserved. Returns true if successful, false otherwise.

def append(self, content, binary=False, encoding=None):
        """Appends the given content to the file. Existing content is
        preserved. Returns true if successful, false otherwise."""
        mode = "ab" if binary else "a"
        return self._write(content, mode, encoding=encoding, linesep=False)