`maskthresh` is not used?

[ysBach]

Make test data first:

import sep
import numpy as np
import pandas as pd

def extractor(data, mask=None, thresh=0., maskthresh=0.0):
    data = data.astype(float)
    if mask is not None:
        mask = mask.astype(float)
    obj, segm = sep.extract(data, thresh=thresh, mask=mask, maskthresh=maskthresh, segmentation_map=True)
    return pd.DataFrame(obj), segm

data = np.array([[0, 10, 0], [10, 100, 10], [0, 10, 0]])
mask = np.array([[0, 1, 0], [1, 2, 1], [0, 1, 0]])

(1) If no mask is provided, maskthresh has no effect, as expected:

extractor(data, maskthresh=0.0)
extractor(data, maskthresh=1.0)
extractor(data, maskthresh=2.0)
# ALL IDENTICAL:
# (   thresh  npix  tnpix  xmin  xmax  ymin  ymax    x    y        x2        y2  \
#  0     0.0     9      5     0     2     0     2  1.0  1.0  0.519231  0.519231   
# ...
# array([[1, 1, 1],
#        [1, 1, 1],
#        [1, 1, 1]], dtype=int32))

(2) If mask is provided, the results are AGAIN identical:

extractor(data, mask, maskthresh=0.0)
extractor(data, mask, maskthresh=2.0)
extractor(data, mask, maskthresh=10.0)
# ALL IDENTICAL:
# (   thresh  npix  tnpix  xmin  xmax  ymin  ymax    x         y   x2        y2  \
#  0     0.0     6      1     0     2     0     1  1.0  0.333333  0.5  0.222222   
# ...
#  array([[1, 1, 1],
#         [1, 1, 1],
#         [0, 0, 0]], dtype=int32))

FYI, the docstring says

   maskthresh : float, optional
        Mask threshold. This is the inclusive upper limit on the mask value in
        order for the corresponding pixel to be unmasked. For boolean arrays,
        `False` and `True` are interpreted as 0 and 1, respectively. Thus,
        given a threshold of zero, True corresponds to masked and `False`
        corresponds to unmasked.

So I expected extractor(data, mask, maskthresh=10.0) should be identical to extractor(data, mask=None). Am I misunderstanding something?