Type checking tuple type for fields causes infinite recursion

[cromachina]

Specifying a tuple type for a field seems to break pyrsistent's type checker.

Pyrsistent version 0.20.0 Python 3.12 Linux (NixOS)

Minimal example test.py:

from pyrsistent import *

IVec2 = tuple[int, int]

class Mask(PClass):
    position = field(type=IVec2)

Load the module:

python -m test.py

Output:

Traceback (most recent call last):
  File "<frozen runpy>", line 189, in _run_module_as_main
  File "<frozen runpy>", line 112, in _get_module_details
  File "/home/cro/aux/Projects/crowpainter/src/crowpainter/test.py", line 5, in <module>
    class Mask(PClass):
  File "/home/cro/aux/Projects/crowpainter/src/crowpainter/test.py", line 6, in Mask
    position = field(type=IVec2)
               ^^^^^^^^^^^^^^^^^
  File "/nix/store/kq39qlgbmj8qib3jc600d1k0pfk1nw3d-python3.12-pyrsistent-0.20.0/lib/python3.12/site-packages/pyrsistent/_field_common.py", line 121, in field
    types = set(maybe_parse_user_type(type))
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^
...
...
  File "/nix/store/kq39qlgbmj8qib3jc600d1k0pfk1nw3d-python3.12-pyrsistent-0.20.0/lib/python3.12/site-packages/pyrsistent/_checked_types.py", line 92, in maybe_parse_user_type
    return tuple(e for t in ts for e in maybe_parse_user_type(t))
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/kq39qlgbmj8qib3jc600d1k0pfk1nw3d-python3.12-pyrsistent-0.20.0/lib/python3.12/site-packages/pyrsistent/_checked_types.py", line 92, in <genexpr>
    return tuple(e for t in ts for e in maybe_parse_user_type(t))
                                        ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/kq39qlgbmj8qib3jc600d1k0pfk1nw3d-python3.12-pyrsistent-0.20.0/lib/python3.12/site-packages/pyrsistent/_checked_types.py", line 81, in maybe_parse_user_type
    is_iterable = isinstance(t, Iterable)
                  ^^^^^^^^^^^^^^^^^^^^^^^
RecursionError: maximum recursion depth exceeded