As shown in microsoft/gather#23, gather will detect methods like np.sin as modifying the np object, thus including these calls in slices where they don't belong.

As an example, consider the following two cells. Try to gather the output of the second cell. You'll find nbgather will gather the line np.sin(10), even though it's not necessary in the slice.

# Cell 1
import numpy as np
np.sin(10)

# Cell 2
print(np.arange(0, 10))