Check if the data type is valid. The data type is valid if it is one of the
elements of the VALID_DATA_TYPES vector. The valid data types are:
c(Median, Net MFI, Count, Avg Net MFI, Mean, Peak).
Check if the data type is valid. The data type is valid if it is one of the
elements of the VALID_DATA_TYPES vector. The valid data types are:
c(Median, Net MFI, Count, Avg Net MFI, Mean, Peak).