def from_file(cls, filename_or_file_object):
        """
        Create new instance of the object from the file.
        :param filename_or_file_object: the filename of the file to read from or already opened file buffer
        :type filename_or_file_object: basestring|file
        """
        object_ = from_file(filename_or_file_object)
        if not isinstance(object_, cls):
            raise ValueError('Expected to read {0!r} object, but got {1!r} instead'.format(cls, type(object_)))

        return object_
Create new instance of the object from the file.
        :param filename_or_file_object: the filename of the file to read from or already opened file buffer
        :type filename_or_file_object: basestring|file