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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 register_pattern(name, pattern_factory, override=None):
 	""" 	Registers the specified pattern factory. 	*name* (:class:`str`) is the name to register the pattern factory 	under. 	*pattern_factory* (:class:`~collections.abc.Callable`) is used to 	compile patterns. It must accept an uncompiled pattern (:class:`str`) 	and return the compiled pattern (:class:`.Pattern`). 	*override* (:class:`bool` or :data:`None`) optionally is whether to 	allow overriding an already registered pattern under the same name 	(:data:`True`), instead of raising an :exc:`AlreadyRegisteredError` 	(:data:`False`). Default is :data:`None` for :data:`False`. 	"""

	if not isinstance(name, string_types):
		raise TypeError("name:{!r} is not a string.".format(name))
	if not callable(pattern_factory):
		raise TypeError("pattern_factory:{!r} is not callable.".format(pattern_factory))
	if name in _registered_patterns and not override:
		raise AlreadyRegisteredError(name, _registered_patterns[name])
	_registered_patterns[name] = pattern_factory