Describe the bug
The following assertion worked until v0.12. Now it returns a TypeError.
To Reproduce
import sparse
import numpy as np
a = np.random.rand(1000,1000)
a[a<.9] = np.nan
a = sparse.COO(a, fill_value=np.nan)
a.fill_value = 0.0
a = sparse.COO(a)
assert a == a