I want to filter some docs in an executor, and found a solution here:
https://docarray.jina.ai/fundamentals/documentarray/access-elements/#index-by-boolean-mask

There are two questions:

1. Is this the only way to filter document offered by docarray?
2. There seems a wrong description here.
   Note that if the length of the boolean mask is smaller than the length of a DocumentArray, then the remaining part is padded to False.
   It seems the True masked doc will be removed and smaller boolean mask is padding with True.

Test code :

da = DocumentArray.empty(3)
mask = [True, False] # has same behave with [True, False, True]
del da[mask]
print(len(da))  # got 1