Fix GPU bench scripts

examples/qed_bench_reduction_steps_gpu.jl

@@ -4,6 +4,7 @@ using UUIDs
 using BenchmarkTools
 using DataFrames
 using CSV
+using Dates
 
 results_filename = "bench_results_reduction_steps_gpu.csv"
 
@@ -39,7 +40,7 @@ function bench(func, inputs)
     gpu_compile_time = @elapsed func.(inputs[1:2])
 
     gpu_time = @benchmark $func.($inputs)
-    
+
     return (
         cpu_compile_time = 0.0,
         gpu_compile_time = gpu_compile_time,
@@ -59,7 +60,7 @@ processes = [("ke->kke", 50), ("ke->ke", 1), ("ke->kke", 1), ("ke->kkke", 1), ("
 for (process_str, STEPSIZE) in processes
     n = 0
     opt_time_cum = 0
-    
+
     # preparation of graph
     machine = Machine(
         [