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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 validate_config(cls, config):
 """ Validates a config dictionary parsed from a cluster config file. Checks that a discovery method is defined and that at least one of the balancers in the config are installed and available. """

        if "discovery" not in config:
            raise ValueError("No discovery method defined.")

        installed_balancers = Balancer.get_installed_classes().keys()

        if not any([balancer in config for balancer in installed_balancers]):
            raise ValueError("No available balancer configs defined.")