code: def get_backpressure_policies(topology: "Topology"):
      data_context = ray.data.DataContext.get_current()
      policies = data_context.get_config(
          ENABLED_BACKPRESSURE_POLICIES_CONFIG_KEY,
          ENABLED_BACKPRESSURE_POLICIES,
      )
  
      return [policy(topology) for policy in policies]
  
imports: from typing import TYPE_CHECKING
  import ray
  from .backpressure_policy import BackpressurePolicy
  from .concurrency_cap_backpressure_policy import ConcurrencyCapBackpressurePolicy
  from .streaming_output_backpressure_policy import StreamingOutputBackpressurePolicy
label_desc: Use image node_id 1 for calling a global function with example usage: get_backpressure_policies(topology) and returns: unknown