Why in some modules, certain classes has two copies of the same method one starts with _?

Question

Sometimes I see classes that has attributes or methods that start with underscore. Why do they do that?

For example: in Tensorflow, a model class has ._layers and .layers methods.

Answer 1

Python has no notion of private members, so underscore is used as a convention to denote private methods or fields.

The underscore prefix is meant as a hint to another programmer that a variable or method starting with a single underscore is intended for internal use. This convention is defined in PEP 8.

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