new_contents: import json
  import pandas as pd
  import argparse
  import re
  from os.path import basename
  
  
  def benchmark_to_df(json_file):
      with open(json_file) as jf:
          content = json.load(jf)
          df = pd.DataFrame(columns=("test", "time [ms] "))
          for b in content["benchmarks"]:
              df = df.append({"test": b["name"],
                              "time [ms] ": b["stats"]["mean"] * 1000.0},
                             ignore_index=True)
          return df
  
  
  if __name__ == "__main__":
      parser = argparse.ArgumentParser(description="""
      compare cobrapy benchmarks.""")
      parser.add_argument('first', help='first branch to compare')
      parser.add_argument('second', help='second branch to compare')
      args = parser.parse_args()
  
      first = benchmark_to_df(args.first)
      second = benchmark_to_df(args.second)
      re_name = '^[0-9]+_(.+).json$'
      first_name = re.findall(re_name, basename(args.first))[0]
      second_name = re.findall(re_name, basename(args.second))[0]
      both = pd.merge(first, second, how="inner", on="test",
                      suffixes=(first_name, second_name))
      both["fraction"] = both.iloc[:, 2] / both.iloc[:, 1]
      both.sort_values(by="fraction")
      print(both)
  
subject: add compare benchmark script