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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def ensure_single_char(func):
 	""" 	Decorator that ensures that the first argument of the decorated function is 	a single character, i.e. a string of length one. 	"""

	@functools.wraps(func)
	def wrapper(*args, **kwargs):
		if not isinstance(args[0], str) or len(args[0]) != 1:
			raise ValueError((
				'This function should be invoked with a string of length one '
				'as its first argument'))
		return func(*args, **kwargs)

	return wrapper