code: def cost_per_hour_from_cores(
      self,
      resource_rates: Dict[str, float],
      utilized_cores_mcpu: int,
  ) -> float:
      assert 0 <= utilized_cores_mcpu <= self.cores * 1000
      memory_in_bytes = cores_mcpu_to_memory_bytes(
          self.cloud, utilized_cores_mcpu, self.worker_type()
      )
      storage_in_gb = 0  # we don't need to account for external storage
      return self.cost_per_hour(
          resource_rates,
          utilized_cores_mcpu,
          memory_in_bytes,
          storage_in_gb,
      )
  
file_path: hail/batch/batch/instance_config.py
imports: import abc
  from typing import Dict, List, Sequence
  from .cloud.resource_utils import cores_mcpu_to_memory_bytes
  from .driver.billing_manager import ProductVersions
  from .resources import QuantifiedResource, Resource
label_desc: Use image node_id 9 for calling the InstanceConfig obj's underlying member method code with example usage: obj.cost_per_hour_from_cores(resource_rates, utilized_cores_mcpu) and returns: self