Replace the digits 1-5 (also in superscript) with Chao tone letters. Equal
	consecutive digits are collapsed into a single Chao letter.

	If inverse=True, smaller digits are converted into higher tones; otherwise,
	they are converted into lower tones (the default).

	Part of ipatok's public API.

def replace_digits_with_chao(string, inverse=False):
	"""
	Replace the digits 1-5 (also in superscript) with Chao tone letters. Equal
	consecutive digits are collapsed into a single Chao letter.

	If inverse=True, smaller digits are converted into higher tones; otherwise,
	they are converted into lower tones (the default).

	Part of ipatok's public API.
	"""
	chao_letters = '˩˨˧˦˥'

	if inverse:
		chao_letters = chao_letters[::-1]

	string = string.translate(str.maketrans('¹²³⁴⁵', '12345'))
	string = string.translate(str.maketrans('12345', chao_letters))

	string = ''.join([
		char for index, char in enumerate(string)
		if not (index and char in chao_letters and string[index-1] == char)])

	return string