# Returns a copy of `self` minus all occurences of `pattern`
	#
	#     assert "__init__".remove_all('_') == "init"
	#     assert "abcd".remove_all("bc") == "ad"
	#     assert "abcd".remove_all("[ad]".to_re) == "bc"
	fun remove_all(pattern: Pattern): String do return split(pattern).join