BUG: Exactly same check multiple times in if statement

[debnathshoham]

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Hi, I stumbled upon this while trying to fix another bug.
Is there a reason for the multiple check below (Lines 3536-3537)?
Should be a quick fix.

pandas/pandas/core/indexes/multi.py

Lines 3533 to 3540 in 8924277

	def _union(self, other, sort) -> MultiIndex:
	other, result_names = self._convert_can_do_setop(other)
	if (
	any(-1 in code for code in self.codes)
	and any(-1 in code for code in self.codes)
	or self.has_duplicates
	or other.has_duplicates
	):

[jreback]

prob 2nd should be other.codes

[phofl]

Yes, fast_unique_multiple does Not match nans iirc