The following codes

`{t,x,y,z,r}::Coordinate; \delta{#}::KroneckerDelta. {i,j,k,l,m,n,o,p,q,s#}::Indices(fourD,values={t,x,y,z},position=independent); {i,j,k,l,m,n,o,p,q,s#}::Integer(range=0..3) xx:=\delta^1_1^2_2; evaluate(_); `

give me the ouput :
`0`

But, in my opinion I should get the value `1/2`

.

Further, I run

`xx2:=\delta^1_1^2_2; expand_delta(_); eliminate_kronecker(_); evaluate(_); `

at last, I get

`RuntimeError: evaluate: Index 1 does not have an Indices property. At: Notebook Cell (Line 1): _ = evaluate(_); display(_) `