# Revert to the previous Namespace context.
	#
	# Normally, you should pop the context at the end of each
	# XML element. After popping the context, all Namespace prefix
	# mappings that were previously in force are restored.
	#
	# You must not attempt to declare additional Namespace
	# prefixes after popping a context, unless you push another
	# context first.
	#
	# SEE: `push_context`
	fun pop_context do
		assert stack_not_empty: context_position > 0
		current_context.clear
		context_position -= 1
		current_context = contexts[context_position]
	end