<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def multi_substitution(*substitutions):
 	""" 	Take a sequence of pairs specifying substitutions, and create 	a function that performs those substitutions. 	'baz' 	"""

	substitutions = itertools.starmap(substitution, substitutions)
	# compose function applies last function first, so reverse the
	#  substitutions to get the expected order.
	substitutions = reversed(tuple(substitutions))
	return compose(*substitutions)