[bug] some inputs to parse lead to pickling errors due to latex2sympy2_extended

[jonathon-reflect]

Thanks for the very useful library :)

This bug came up when trying to run math_verify.parse in separate processes, which lead to the following error:

"/usr/local/lib/python3.12/concurrent/futures/process.py", line 432, in wait_result_broken_or_wakeup 
result_item = result_reader.recv()
"/usr/local/lib/python3.12/multiprocessing/connection.py", line 251, in recv
return _ForkingPickler.loads(buf.getbuffer())
"/lib/python3.12/site-packages/latex2sympy2_extended/logic.py", line 11, in __new__ 
obj._unsorted_args = args
AttributeError: 'Equality' object has no attribute '_unsorted_args'

After a bunch of digging and testing I think the issue is due to the latex2sympy2_extended parser creating relational args with evaluate=False, but sympy's __getnewargs__ doesn't preserve that kwarg so during unpickling, numeric comparisons re-evaluate to True, LatticeOp filters them as identity elements, and And.__new__ returns a non-And type that crashes on _unsorted_args assignment.

I encountered this in latex2sympy2_extended 1.11.0 with sympy 1.14.0

I was able to reproduce the errors with:

import pickle

import math_verify

FAILING_INPUTS = [
  r'\boxed{0 < 1 < x}',
  r'\boxed{1 = 1 = x}',
  r'\boxed{x > 3 > 1}',
]

for pred in FAILING_INPUTS:
  parsed = math_verify.parse(pred)
  data = pickle.dumps(parsed)
  pickle.loads(data)

I am not deeply familar with the exact working of latex2sympy2 or sympy so definitely treat this as a best guess.