## 4.1.1 String constants

The constants defined in this module are:

`ascii_letters`
  The concatenation of the `ascii_lowercase` and `ascii_uppercase` constants described below. This value is not locale-dependent.

`ascii_lowercase`
  The lowercase letters `'abcdefghijklmnopqrstuvwxyz'`. This value is not locale-dependent and will not change.

`ascii_uppercase`
  The uppercase letters `'ABCDEFGHIJKLMNOPQRSTUVWXYZ'`. This value is not locale-dependent and will not change.

`digits`
  The string `'0123456789'`.

`hexdigits`
  The string `'0123456789abcdefABCDEF'`.

`letters`
  The concatenation of the strings `lowercase` and `uppercase` described below. The specific value is locale-dependent, and will be updated when `locale.setlocale()` is called.

`lowercase`
  A string containing all the characters that are considered lowercase letters. On most systems this is the string `'abcdefghijklmnopqrstuvwxyz'`. Do not change its definition -- the effect on the routines `upper()` and `swapcase()` is undefined. The specific value is locale-dependent, and will be updated when `locale.setlocale()` is called.

`octdigits`
  The string `'01234567'`.

`punctuation`
  String of ASCII characters which are considered punctuation characters in the "`C`" locale.

`printable`
  String of characters which are considered printable. This is a combination of `digits`, `letters`, `punctuation`, and `whitespace`.

`uppercase`
  A string containing all the characters that are considered uppercase letters. On most systems this is the string `'ABCDEFGHIJKLMNOPQRSTUVWXYZ'`. Do not change its definition -- the effect on the routines `lower()` and `swapcase()` is undefined. The specific value is locale-dependent, and will be updated when `locale.setlocale()` is called.

`whitespace`
  A string containing all characters that are considered whitespace. On most systems this includes the characters space, tab, linefeed, return, formfeed, and vertical tab. Do not change its definition -- the effect on the routines `strip()` and `split()` is undefined.