new_contents: import csv
  
  # install fabric version < 2 following script is for less than v2.0
  # $pip install 'fabric<2.0'
  
  from fabric.api import env, parallel, run, task
  
  from fabric.colors import green, red, yellow
  from fabric.state import output
  
  env.user = '<ssh-user-name>'
  env.warn_only = True
  #env.use_ssh_config = True
  output['running'] = False
  output['stdout'] = False
  
  @task
  def set_servers(server_group):
      env.servers = get_server_list(server_group)
  
  def get_server_list(server_group):
      servers_list = []
      with open('my-servers.csv', 'rU') as serverlistfile:
          reader = csv.DictReader(serverlistfile)
          for row in reader:
              server = row[server_group]
              if (server and server.strip()):
                  servers_list.append(server)
      return servers_list
  
  @parallel(pool_size=5)
  @task
  def echo_server_name():
     for host in env.hosts:
         print host
         
  
subject: Create fabfile.py