from pydantic import BaseModel

class BarModel(BaseModel):
    whatever: int

class FooBarModel(BaseModel):
    banana: float
    foo: str
    bar: BarModel

m = FooBarModel(banana=3.14, foo='hello', bar={'whatever': 123})

print(m.copy(include={'foo', 'bar'}))
# > FooBarModel foo='hello' bar=<BarModel whatever=123>

print(m.copy(exclude={'foo', 'bar'}))
# > FooBarModel banana=3.14

print(m.copy(update={'banana': 0}))
# > FooBarModel banana=0 foo='hello' bar=<BarModel whatever=123>

print(id(m.bar), id(m.copy().bar))
# normal copy gives the same object reference for `bar`
# > 140494497582280 140494497582280

print(id(m.bar), id(m.copy(deep=True).bar))
# deep copy gives a new object reference for `bar`
# > 140494497582280 140494497582856