def guess_dtype(data):
    """ Attempt to guess an appropriate dtype for the object, returning None
    if nothing is appropriate (or if it should be left up the the array
    constructor to figure out)
    """
    """
    # todo
    with phil:
        if isinstance(data, h5r.RegionReference):
            return h5t.special_dtype(ref=h5r.RegionReference)
        if isinstance(data, h5r.Reference):
            return h5t.special_dtype(ref=h5r.Reference)
        if type(data) == bytes:
            return h5t.special_dtype(vlen=bytes)
        if type(data) == six.text_type:
           return h5t.special_dtype(vlen=six.text_type)
    """
    return None
