It depends what you mean by coercion. For instance:
class Foo:
def __getitem__(self, x):
return x
i = iter(Foo())
print(next(i))
print(next(i))
That works because any object that provides __getitem__ "implements the iterable protocol."[1] I bring up __getitem__ because people familiar with Java are scratching their heads, "not only did you not declare any interfaces, this is just a convention, but there's also an __iter__ method. Huh?"
But interfaces are just one way to declare a type. The question is, did it convert it to a new type?
Well, what type was it before? If you want to talk about LSP[0], you're a bit stuck here since you can't prove anything about a method in python. (And here, we declared its type, and we said nothing about it being iterable or a sequence.) You have to run it because you don't know that a. Foo has __iter__ or __getitem__, b. that they accept the arguments you're going to pass, c. let alone that they're designed to, d. that the object won't simply delete them halfway through.
All that iter() is going to do is look for those methods and make assumptions that if you wrote __getitem__ that you meant it. At which point maybe LSP works, after all, you'll prove that it has that property by running the code and fixing it if it breaks.
But... python nevertheless will nevertheless construct this proxy to use your class based on inspection, which seems an awful lot like coercion to me.
[0]: Quoth Wikipedia: Let 𝜙(𝑥) be a property provable about objects 𝑥 of type T. Then 𝜙(𝑦) should be true for objects 𝑦 of type S where S is a subtype of T.
[1]: https://docs.python.org/3/glossary.html#term-iterable