Fraction masks raises error

[osbm]

Here is the minimal code that reproduces the error.

from fastmri.data.subsample import create_mask_for_mask_type
from fastmri.data.transforms import apply_mask, to_tensor, center_crop
import numpy as np

mask_func =create_mask_for_mask_type(
    mask_type_str="magic_fraction",
    center_fractions=[0.37],
    accelerations=[4]
)

kspace = np.load("data/prostate1_kspace.npy")
print(kspace.shape) # (34, 14, 640, 451)
kspace = to_tensor(kspace)
print(kspace.shape) # torch.Size([34, 14, 640, 451, 2])
subsampled_kspace, mask, num_low_frequencies = apply_mask(
    kspace,
    mask_func,
    seed=1
)

The error:

Traceback (most recent call last):
  File "test.py", line 15, in <module>
    subsampled_kspace, mask, num_low_frequencies = apply_mask(
                                                   ^^^^^^^^^^^
  File ".venv/lib/python3.12/site-packages/fastmri/data/transforms.py", line 77, in apply_mask
    mask, num_low_frequencies = mask_func(shape, offset, seed)
                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File ".venv/lib/python3.12/site-packages/fastmri/data/subsample.py", line 105, in __call__
    center_mask, accel_mask, num_low_frequencies = self.sample_mask(
                                                   ^^^^^^^^^^^^^^^^^
  File ".venv/lib/python3.12/site-packages/fastmri/data/subsample.py", line 469, in sample_mask
    self.calculate_acceleration_mask(
  File ".venv/lib/python3.12/site-packages/fastmri/data/subsample.py", line 384, in calculate_acceleration_mask
    offset = self.rng.randint(0, high=acceleration)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "numpy/random/mtrand.pyx", line 798, in numpy.random.mtrand.RandomState.randint
  File "numpy/random/_bounded_integers.pyx", line 1334, in numpy.random._bounded_integers._rand_int64
ValueError: high <= 0

But this works fine when mask_type_str is equal to the equispaced, random, magic but not the equispaced_fraction or magic_fraction.

I might be missing something as i dont understand what adding "fraction" changes in the behaviour of the masking function.