table = str.maketrans('', '', string.punctuation)

This line of code creates a translation table that can be used to remove all punctuation marks from a string. Specifically, it uses the string method `maketrans()` to create a translation table that maps each punctuation mark to None (i.e. it removes them from the string). The first two arguments of `maketrans()` are empty strings, which means that no characters will be replaced by other characters. The third argument, `string.punctuation`, is a predefined string in the `string` module that contains all punctuation marks.

This translation table can be passed to the `translate()` method of a string to remove all punctuation marks. For example:

text = "Hello, world!"
clean_text = text.translate(table)
print(clean_text)   # Output: "Hello world"

Here, `table` is the translation table created by `maketrans()`, and `clean_text` is the original text with all punctuation marks removed.