old_contents: # vim:fileencoding=utf-8:noet
  from __future__ import (unicode_literals, division, absolute_import, print_function)
  
  from powerline.bindings.tmux import get_tmux_output
  
  
  def attached_clients(pl, minimum=1):
  	'''Return the number of tmux clients attached to the currently active session
  
  	:param int minimum:
  		The minimum number of attached clients that must be present for this 
  		segment to be visible.
  	'''
  	session_output = get_tmux_output('list-panes', '-F', '#{session_name}')
  	if not session_output:
  		return None
  	session_name = session_output.rstrip().split('\n')[0]
  
  	attached_clients_output = get_tmux_output('list-clients', '-t', session_name)
  	attached_count = len(attached_clients_output.rstrip().split('\n'))
  
  	return None if attached_count < minimum else str(attached_count)
  
new_contents: # vim:fileencoding=utf-8:noet
  from __future__ import (unicode_literals, division, absolute_import, print_function)
  
  from powerline.bindings.tmux import get_tmux_output
  
  
  def attached_clients(pl, minimum=1):
  	'''Return the number of tmux clients attached to the currently active session
  
  	:param int minimum:
  		The minimum number of attached clients that must be present for this 
  		segment to be visible.
  	'''
  	session_output = get_tmux_output(pl, 'list-panes', '-F', '#{session_name}')
  	if not session_output:
  		return None
  	session_name = session_output.rstrip().split('\n')[0]
  
  	attached_clients_output = get_tmux_output(pl, 'list-clients', '-t', session_name)
  	attached_count = len(attached_clients_output.rstrip().split('\n'))
  
  	return None if attached_count < minimum else str(attached_count)
  
subject: Add missing argument to get_tmux_output