The string type is widely used in Python. A string consists of a sequence of characters, even if the sequence length is 1–Python does not make a distinction between a character and a one-character string. The string is a compound type and immutable. The representation of a single character internally in the computer as a sequence of bits is called the encoding. Individual characters are represented either by the ASCII standard (1 byte per character) or Unicode (2-4 bytes per character). Strings that are to be treated as Unicode are type unicode rather than string, but otherwise behave similarly. The default encoding may depend on the operating system but in newer Python versions is usually a standard called utf-8. UTF-8 can represent over one hundred thousand characters and can embed different scripts within the same text file.