When x is a SingleCellAssay and y is a vector, data.frame or AnnotatedDataFrame,
an attempt is made bind it to the columns of the cellData or featureData.
The behavior depends on the number of rows/length of y.
If nrow(y) == nrow(x), then the cellData is used.
If nrow(y) == ncol(x), then the cellData is used.
It is an error if neither mathces.
# S4 method for SingleCellAssay,ANY
combine(x, y, ...)SingleCellAssay
vector, data.frame or AnnotatedDataFrame
ignored
SingleCellAssay