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  • Chris Kang thinks this is interesting:

Like lists and dictionaries, tuples support mixed types and nesting, but they don’t grow and shrink because they are immutable (the parentheses enclosing a tuple’s items can often be omitted, as done here; in contexts where commas don’t otherwise matter, the commas are what actually builds a tuple):

From

Cover of Learning Python, 5th Edition

Note

Comma between 'span' and 3.0 and 3.0 and [11,...] makes this a tuple.