I have a string variable I've defined in one Jupyter notebook that I'd like to use in another Jupyter notebook. I know from here that %store is an approach, but when I use %store -r <variable> in either Jupyter notebook, I obtain the below errors ending in

TypeError: 'PickleShareDB' object is not subscriptable when using %store

Below is the full output. I installed pickleshare by running pip install pickleshare in terminal.

Trying to use %store -r in Jupyter notebook A (notebook where string variable defined)

# Retrieving stored string_var from notebook A
from pickleshare import *
string_var = "hi"
%store string_var
%store -r string_var

Stored 'string_var' (str)

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
Cell In[27], line 5
      4 get_ipython().run_line_magic('store', 'string_var')
----> 5 get_ipython().run_line_magic('store', '-r string_var')

File ~/Library/Python/3.9/lib/python/site-packages/IPython/core/interactiveshell.py:2456, in InteractiveShell.run_line_magic(self, magic_name, line, _stack_depth)
   2454     kwargs['local_ns'] = self.get_local_scope(stack_depth)
   2455 with self.builtin_trap:
-> 2456     result = fn(*args, **kwargs)
   2458 # The code below prevents the output from being displayed
   2459 # when using magics with decorator @output_can_be_silenced
   2460 # when the last Python token in the expression is a ';'.
   2461 if getattr(fn, magic.MAGIC_OUTPUT_CAN_BE_SILENCED, False):

File ~/Library/Python/3.9/lib/python/site-packages/IPython/extensions/storemagic.py:148, in StoreMagics.store(self, parameter_s)
    146 for arg in args:
    147     try:
--> 148         obj = db['autorestore/' + arg]
    149     except KeyError:
    150         try:

TypeError: 'PickleShareDB' object is not subscriptable

Trying to use %store -r in Jupyter notebook B, where I'd like to retrieve string_var from notebook A

# Retrieving stored string_var from notebook A
from pickleshare import *
%store -r string_var

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
Cell In[37], line 2
      1 from pickleshare import *
----> 2 get_ipython().run_line_magic('store', '-r string_var')

File ~/Library/Python/3.9/lib/python/site-packages/IPython/core/interactiveshell.py:2456, in InteractiveShell.run_line_magic(self, magic_name, line, _stack_depth)
   2454     kwargs['local_ns'] = self.get_local_scope(stack_depth)
   2455 with self.builtin_trap:
-> 2456     result = fn(*args, **kwargs)
   2458 # The code below prevents the output from being displayed
   2459 # when using magics with decorator @output_can_be_silenced
   2460 # when the last Python token in the expression is a ';'.
   2461 if getattr(fn, magic.MAGIC_OUTPUT_CAN_BE_SILENCED, False):

File ~/Library/Python/3.9/lib/python/site-packages/IPython/extensions/storemagic.py:148, in StoreMagics.store(self, parameter_s)
    146 for arg in args:
    147     try:
--> 148         obj = db['autorestore/' + arg]
    149     except KeyError:
    150         try:

TypeError: 'PickleShareDB' object is not subscriptable

Thank you.