1# Copyright 2000-2002 by Andrew Dalke.
2# Revisions copyright 2007-2010 by Peter Cock.
3# All rights reserved.
4#
5# This file is part of the Biopython distribution and governed by your
6# choice of the "Biopython License Agreement" or the "BSD 3-Clause License".
7# Please see the LICENSE file that should have been included as part of this
8# package.
9"""Alphabets were previously used to declare sequence type and letters (OBSOLETE).
10
11The design of Bio.Aphabet included a number of historic design choices
12which, with the benefit of hindsight, were regretable. Bio.Alphabet was
13therefore removed from Biopython in release 1.78. Instead, the molecule type is
14included as an annotation on SeqRecords where appropriate.
15
16Please see https://biopython.org/wiki/Alphabet for examples showing how to
17transition from Bio.Alphabet to molecule type annotations.
18"""
19
20raise ImportError(
21    "Bio.Alphabet has been removed from Biopython. In many cases, the alphabet can simply be ignored and removed from scripts. In a few cases, you may need to specify the ``molecule_type`` as an annotation on a SeqRecord for your script to work correctly. Please see https://biopython.org/wiki/Alphabet for more information."
22)
23