Get the summary from a stype variable
get_data_summary(x, element)
# S4 method for stype,ANY
get_data_summary(x, element)
# S4 method for stype,character
get_data_summary(x, element)the object from which to get the data_summary
either NULL to get the full data_summary
or a length 1 character to select a particular element of the summary