def _which(sym, _larch=None, **kws):
    if _larch is None:
        raise Warning("cannot run which() -- larch broken?")
    stable = _larch.symtable
    if hasattr(sym, '__name__'):
        sym = sym.__name__
    if isinstance(sym, (str, unicode)) and stable.has_symbol(sym):
        obj = stable.get_symbol(sym)
        if obj is not None:
            return '%s.%s' % (stable.get_parentpath(sym), sym)
    return None
return full path of object, or None if object cannot be found
dataset/ETHPy150Open xraypy/xraylarch/lib/builtins.py/_which