Python: Generate a random string of given length from a select range of characters (A T G C) [duplicate]

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• Random string generation with upper case letters and digits in Python 21 answers

I need to write a code in python that generates a random string of given length from a select range of characters (A T G C).

I have tried to use the random function however I am finding it difficult to limit the characters to just the four I want, while keeping the sequence length unlimited.