code: def check_dts(requested_dts):
      """Validate that ``requested_dts`` are valid for querying from an FX reader."""
      if not is_sorted_ascending(requested_dts):
          raise ValueError("Requested fx rates with non-ascending dts.")
  
label_desc: Use image node_id 1 for calling a global function with example usage: check_dts(requested_dts) without return types