'operator is invalid for atomic vectors' error

[soo-ni42]

I am analyzing using 'CellChat'.
While running the code following the tutorial document, the following error occurred.

gg1 <- compareInteractions(cellchat, show.legend = F, group = c(1, 2))
The following error occurred at h(simpleError(msg, call)):
 An error occurred evaluating argument 'x' when selecting method for function 'as.data.frame': $ operator is invalid for atomic vectors

Why does this error occur and how can I fix it?
Has anyone ever encountered an error like this?

[soo-ni42]

I solved it! The error occured because I didn't merge cellchat objects!