fda and instrument amplifier example failing

[hconboe]

Trying to run the fully differential opamp example on the tutorial

from lcapy import Circuit, t, oo

a = Circuit(r"""
Vsp 1 0_1 ; down
W 0_1 0; down=0.1, 0V
W 1 1_1; right
R1 1_1 6; right
Vsm 2 0_3 ; down
W 0_3 0; down=0.05, 0V
R3 2 3; right
E1 5_2 4_2 fdopamp 3 6 0_4 A; right, mirror, l
W 5_2 5; right
W 4_2 4; right
P2 5 4; down
W 5_1 5_2; down
W 6_1 6; down
W 3 3_1; down
R2 6_1 5_1; right
W 4_2 4_1; down
R4 3_1 4_1; right
W 0 0_4; right=0.4
W 0 0_2; down=0.01, 0V
; draw_nodes=connected
""")

a.draw()

b = a.subs({'R4': 'R2', 'R3': 'R1'})

The above works fine, however, when I get to the line

Vod = (b[5].V(t) - b[4].V(t)).simplify()

I get the following error

File "", line 1, in
File "C:\Python312\Lib\site-packages\lcapy\node.py", line 74, in V
return self.cct.get_Vd(self.name, '0')
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Python312\Lib\site-packages\lcapy\netlist.py", line 319, in get_Vd
return self._get_Vd(Np, Nm, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Python312\Lib\site-packages\lcapy\netlist.py", line 306, in _get_Vd
subs = self._subs_make(nowarn=nowarn)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Python312\Lib\site-packages\lcapy\netlist.py", line 109, in _subs_make
cct = self.expand()
^^^^^^^^^^^^^
File "C:\Python312\Lib\site-packages\lcapy\netlist.py", line 652, in expand
new._add(cpt._expand())
^^^^^^^^^^^^^
File "C:\Python312\Lib\site-packages\lcapy\mnacpts.py", line 1274, in _expand
opampp = self._netmake_expand('Ep',
^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Python312\Lib\site-packages\lcapy\mnacpts.py", line 440, in _netmake_expand
return self._netmake1(name, nodes, args, opts, ignore_keyword=True)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Python312\Lib\site-packages\lcapy\mnacpts.py", line 397, in _netmake1
parts.append(node.name)
^^^^^^^^^
AttributeError: 'str' object has no attribute 'name'

I get similar errors from running the instrument amplifier example