How does functools.singledispatch enable function overloading based on argument type?

singledispatch turns a function into a generic function that dispatches to type-specific implementations registered with @func.register(Type). The base function acts as the default implementation, and Python picks the most specific matching registered implementation based on the first argument's runtime type.

from functools import singledispatch

@singledispatch
def describe(obj):
    return f'object: {obj}'

@describe.register
def _(obj: int):
    return f'integer: {obj}'

@describe.register
def _(obj: list):
    return f'list of {len(obj)} items'

print(describe(5), describe([1,2,3]))