Load from file.

        Parameters
        ----------
        fp : `str` or `file`
            File or path.
        storage : `type`, optional
            Storage class (default: cls.DEFAULT_STORAGE)

        Returns
        -------
        `markovchain.Markov`

def from_file(cls, fp, storage=None):
        """Load from file.

        Parameters
        ----------
        fp : `str` or `file`
            File or path.
        storage : `type`, optional
            Storage class (default: cls.DEFAULT_STORAGE)

        Returns
        -------
        `markovchain.Markov`
        """
        if storage is None:
            storage = cls.DEFAULT_STORAGE
        return cls.from_storage(storage.load(fp))