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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_validators(cls, bigchain, height=None):
 """Return a dictionary of validators with key as `public_key` and value as the `voting_power` """

        validators = {}
        for validator in bigchain.get_validators(height):
            # NOTE: we assume that Tendermint encodes public key in base64
            public_key = public_key_from_ed25519_key(key_from_base64(validator['public_key']['value']))
            validators[public_key] = validator['voting_power']

        return validators