`fusionblockstructure` with argument of the type `TensorMapSpace` error

[Chenqitrg]

Hi, developers,

I find that in the newest version of TensorKit, the fusionblockstructure does not work:

V = Z2Space(1=>1)
zeros(Float64,V←V) # error: fusionblockstructure for TensorMapSpace not defined

So I directly write

TensorKit.fusionblockstructure(V←V) # error

In the old version of TensorKit, it returns no error.
Perhaps because of the change in this line in homspace?