@classmethod
def from_file(cls, filename: str) ->'DropletTrack':
    """ create droplet track by reading from file
        
        Args:
            filename (str): Name of the file to read emulsion from
        """
    import h5py
    with h5py.File(filename, 'r') as fp:
        if len(fp) != 1:
            raise RuntimeError(
                f'Multiple droplet track were found in the file {filename})')
        dataset = fp[list(fp.keys())[0]]
        obj = cls._from_hdf_dataset(dataset)
    return obj
