The command

$\texttt{K_{i j k}::TableauSymmetry( shape={2,1}, indices={1,2,0} );}$

defines a tensor which is antisymmetric in $i$ and $j$ and satisfies the Bianchi identity. How can I define a tensor which is *symmetric* in $i$ and $j$ and satisfies the Bianchi identity?

Apparently, $\texttt{cadabra}$ uses the convention "first symmetrise over rows, then antisymmetrise over columns" for filled Young tableaux, whereas I need the opposite convention, i.e."first antisymmetrise over columns, then symmetrise over rows".