message: Update DataFrame.h
  Minor fix
diff: @@ -108,7 +108,7 @@ using DataFrameView = DataFrame<TS, HeteroView>;
  template<typename TS, typename HETERO>
  class DataFrame : public ThreadGranularity {
  - static_assert(std::is_base_of<HeteroVector, HETERO>::value or
  + static_assert(std::is_base_of<HeteroVector, HETERO>::value ||
  std::is_base_of<HeteroView, HETERO>::value,
  "HETERO argument can only be either of "
  "HeteroVector or HeteroView or their derived types");
  