A = 
[[0,1,2]
 [10,11,12]]
SLICE : A(0,range(0,3))  [0,1,2]
A = 
[[0,0,0]
 [0,0,0]]
SLICE : A(0,range(0,3))  [0,0,0]
A is 
[[0,1,2]
 [10,11,12]]
SLICE : A(0,range(0,3))  [0,1,2]
Setting A(0,0) =56 
A is 
[[56,1,2]
 [10,11,12]]
SLICE : A(0,range(0,3))  [56,1,2]