In [21]: obj[re.split('\.', txt, 1)[0]]
Out[21]: 
['Assume formlessness',
 'Those who know do not speak, those who speak do not know']

In [22]: obj[re.split('\.', txt, 1)[0]][1]
Out[22]: 'Those who know do not speak, those who speak do not know'

In [23]: obj[re.split('\.', txt, 1)[0]][0]
Out[23]: 'Assume formlessness'

In [24]: obj[re.split('\.', txt, 1)[0]][re.split('\.', txt, 1)[1]]
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-24-772396cafe64> in <module>
----> 1 obj[re.split('\.', txt, 1)[0]][re.split('\.', txt, 1)[1]]

TypeError: list indices must be integers or slices, not str

In [25]: obj[re.split('\.', txt, 1)[0]][int(re.split('\.', txt, 1)[1])]
Out[25]: 'Those who know do not speak, those who speak do not know'