I can't speak for GP, but I like to use single quotes for symbolic strings ('go_left', 'parent', 'alpha-campus', some_map['fixed_key']) and double quotes for textual strings ("An error occurred", "package/__main__.py").
return '<a href="{}">{}</a>'.format(url, text)
return "<a href=\"{}\">{}</a>".format(url, text)
If you want the behaviour of Ruby strings, you might use a `bytes` or `bytearray` type, or you might use a list of chars.
But at any rate I wasn't thinking of performance characteristics but rather the stereotypical uses of symbols vs strings in languages that have both, so you are right that one can use Python strings in place of symbols, as SpaceManiac already pointed out above.
In Python, string literals are reused, if that is what you meant.
>>> a = 'abc'
>>> b = 'abc'
>>> a is b
Truesome_dict = {'key': "value"}