BUG: Fix import error on Mac

[YibinLiu666]

What do these changes do?

Related issue number

Related #65

Check code requirements

• [ ] tests added / passed (if needed)
• [ ] Ensure all linting tests pass

[codecov[bot]]

Codecov Report

Merging #66 (751cd93) into main (708b539) will increase coverage by 5.26%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main      #66      +/-   ##
==========================================
+ Coverage   83.53%   88.79%   +5.26%     
==========================================
  Files          46       47       +1     
  Lines        3839     3928      +89     
  Branches      744      757      +13     
==========================================
+ Hits         3207     3488     +281     
+ Misses        545      353     -192     
  Partials       87       87              

Flag	Coverage Δ
unittests	88.62% <100.00%> (+5.16%)	:arrow_up:

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
python/xoscar/collective/common.py	100.00% <100.00%> (+11.90%)	:arrow_up:
python/xoscar/collective/core.py	78.20% <100.00%> (ø)
python/xoscar/collective/process_group.py	56.99% <100.00%> (+0.89%)	:arrow_up:
python/xoscar/collective/utils.py	58.82% <100.00%> (ø)

... and 9 files with indirect coverage changes