How exactly does random.random() work in python?

I am a bit confused about how the random.random() function works in python.

The docs say that it 'Return the next random floating point number in the range [0.0, 1.0)'. I understand that pseudo-random number generators work by performing some operation on a value. Generally this value is the previous number generated by the generator. So I think that's what 'next random floating point' means here. (Please correct me if I am wrong)

But when I saw the source code of the random library, random function is not defined in the class Random. Instead, its defined in the class SystemRandom as follows (line 671 of the code):

 def random(self):
        """Get the next random number in the range [0.0, 1.0)."""
        return (int.from_bytes(_urandom(7), 'big') >> 3) * RECIP_BPF

If I understand this correctly, this function generates a random number using os.urandom. Which, according to the documentation, returns random bytes from an OS-specific randomness source. So this will not give the 'next' floating point random number.

How are the two connected? or are they two different things?

I am quite confused here. Any kind of help would be appreciated.

Thanks!