setitem indexing with Lists

[mtar]

Description setitem raises an TypeError when a list is used for indexing along the split axis .

To Reproduce Steps to reproduce the behavior:

1. Which module/class/function is affected? setitem
2. What are the circumstances under which the bug appears? indexing along the split axis
3. What is the exact error message / erroneous behavior?

   [1,1]<stderr>:  File "lib/python3.8/site-packages/heat/core/dndarray.py", line 1639, in __setitem__
   [1,1]<stderr>:    key[self.split] -= chunk_start
   [1,1]<stderr>:TypeError: unsupported operand type(s) for -=: 'list' and 'int'

Expected behavior accept lists

Illustrative

import heat as ht

a = ht.arange(3, split=0)
a[[0,1]] = a[[1,0]]
print(a)

Version Info master

[ClaudiaComito]

Addressed in #938

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Reviewed within #1109

[github-actions[bot]]

Branch bugs/918-setitem_indexing_with_Lists created!

[github-actions[bot]]

This issue is stale because it has been open for 60 days with no activity.