code: def returned(n):
  	
  	## `takei` yield lazily so we can short-circuit and avoid computing the rest of the walk
  	for pos in randwalk() >> drop(1) >> takei(xrange(n-1)):
  		if pos == Origin:
  			return True
  	return False
docs: Generate a random walk and return True if the walker has returned to
  	the origin after taking `n` steps.