code: def pricing_expression_to_price_per_unit(
      pricing_expression: dict,
  ) -> float:
      # https://cloud.google.com/billing/docs/reference/rest/v1/services.skus/list
      # https://cloud.google.com/billing/docs/reference/rest/v1/services.skus/list#Money
      assert len(pricing_expression["tieredRates"]) == 1, str(
          pricing_expression
      )
      unit_price = pricing_expression["tieredRates"][0]["unitPrice"]
      assert unit_price["currencyCode"] == "USD", str(
          pricing_expression
      )
      return int(unit_price["units"]) + (
          unit_price["nanos"] / 1000 / 1000 / 1000
      )
  
imports: import logging
  from typing import AsyncGenerator, List, Optional
  from hailtop.aiocloud import aiogoogle
  from hailtop.utils import rate_cpu_hour_to_mcpu_msec, rate_gib_hour_to_mib_msec, rate_gib_month_to_mib_msec, rate_instance_hour_to_fraction_msec
  from hailtop.utils.time import parse_timestamp_msecs
  from ....driver.pricing import Price
  from ..resources import GCPAcceleratorResource, GCPComputeResource, GCPLocalSSDStaticSizedDiskResource, GCPMemoryResource, GCPStaticSizedDiskResource
label_desc: Use image node_id 2 for calling a global function with example usage: pricing_expression_to_price_per_unit(pricing_expression) and returns: unknown