old_contents: 
  import time
  from jinja2 import Template, Environment, FileSystemLoader
  
  # env = Environment(loader=FileSystemLoader('.'))
  # src = open('index.html').read()
  
  # print env._generate(env._parse(src, 'poop', 'hello.html'),
  #                     'poop',
  #                     'hello.html')
  
  env = Environment(loader=FileSystemLoader('.'))
  times = []
  
  for i in range(100):
      env = Environment(loader=FileSystemLoader('.'))
      t1 = time.time()
      tmpl = env.get_template('index.html')
      tmpl.render({'username': 'james',
                   'arr': [5]*1000})
      t2 = time.time()
  
      times.append(t2-t1)
  
  print reduce(lambda x, y: x+y, times) / len(times)
  
new_contents: 
  import time
  from jinja2 import Template, Environment, FileSystemLoader
  
  # env = Environment(loader=FileSystemLoader('.'))
  # src = open('index.html').read()
  
  # print env._generate(env._parse(src, 'poop', 'hello.html'),
  #                     'poop',
  #                     'hello.html')
  
  env = Environment(loader=FileSystemLoader('.'))
  times = []
  arr = [5]*1000
  
  for i in range(100):
      env = Environment(loader=FileSystemLoader('.'))
      t1 = time.time()
      tmpl = env.get_template('index.html')
      tmpl.render({'username': 'james',
                   'arr': arr})
      t2 = time.time()
  
      times.append(t2-t1)
  
  print reduce(lambda x, y: x+y, times) / len(times)
  
subject: tweak benchmark