How to recover the mro of a class given its bases?

Suppose we are implementing a metaclass that needs to know the method resolution order before the class is instantiated.

class Meta(type):
    def __new__(cls, name, bases, namespace):
        mro = ...

Is there a builtin way to compute the mro, that is a way other than reimplementing the C3 algorithm?

It turns out the functools module has a _c3_merge function that implements the C3 linearization algorithm:

import functools

def compute_mro(*bases):
  return functools._c3_merge(base.mro() for base in bases)

# Example:
class F: pass

class E: pass

class D: pass

class C(D,F): pass

class B(D,E): pass

class A(B,C): pass

print(compute_mro(B, C)) # [B, C, D, E, F, object]

print(A.mro()) # [A, B, C, D, E, F, object]