Formats (prettyprint) a concatenated dictionary

def pp(el,preString=''):
	""" 
	Formats (prettyprint) a concatenated dictionary
	"""
	tab=' '*4
	if isinstance(el,dict):
		keys=list(el.keys())
		keys.sort()
		for key in keys:
			val=el[key]
			if isinstance(val,dict) or isinstance(val,list):
				print('%s%s :' % (preString,key))
				pp(val,preString+tab)
			else:
				print('%s%s  =  %s' % (preString,key,val))
	
	elif isinstance(el,list):
		print(preString+tab+'[')
		preString+=tab	
		for _ in el:
			if isinstance(_,dict):
				print (preString+tab+'{')
				pp(_,preString+tab*2)
				print(preString+tab+'}')
			elif isinstance(_,list):
				print(preString+tab+'[')
				pp(_,preString+tab)
				print(preString+tab+']')
			else:
				pp(_,preString+tab)
			#print preString+'      '+str('-')*10            
		print(preString	+']')
	else:
		print(preString+str(el))