Add note about dynamically created model pickling

[hramezani]

Closes #4178

Selected Reviewer: @tpdorsey

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[hramezani]

please review

[samuelcolvin]

LGTM, best to assign to @tpdorsey for docs PRs.

[tpdorsey]

I may be missing something about this. Would the following capture the same meaning?

"Pickle will work for a dynamically created model only if the model was defined globally, specifying both its class name and the module in which the class was defined."

[hramezani]

@tpdorsey I just copied the description from

pydantic/tests/test_create_model.py

Lines 46 to 56 in 793b484

	def test_create_model_pickle(create_module):
	"""
	Pickle will work for dynamically created model only if it was defined globally with its class name
	and module where it's defined was specified
	"""
	@create_module
	def module():
	import pickle
	from pydantic import create_model

It may help you to understand it better.

I think the dynamic model has to have these two conditions to be pickable:

• Has to provide __module__
• Has to be defined globally. So, defining a dynamic model in function doesn't work

[tpdorsey]

This works, I'll edit the above to use this language. Thx

[tpdorsey]

Minor suggested edit

[tpdorsey]

This works, I'll edit the above to use this language. Thx

[hramezani]

Thanks @tpdorsey for your suggestion