old_contents: from abc import abstractmethod
  from typing import Generator
  
  from .range_partition import PostgresRangePartition
  
  
  class PostgresRangePartitioningStrategy:
      """Base class for implementing a partitioning strategy for a range
      partitioned table."""
  
      @abstractmethod
      def to_create(
          self,
      ) -> Generator[PostgresRangePartition, None, None]:
          """Generates a list of partitions to be created."""
  
      @abstractmethod
      def to_delete(
          self,
      ) -> Generator[PostgresRangePartition, None, None]:
          """Generates a list of partitions to be deleted."""
  
  
  __all__ = ["PostgresRangePartitioningStrategy"]
  
new_contents: from .strategy import PostgresPartitioningStrategy
  
  
  class PostgresRangePartitioningStrategy(PostgresPartitioningStrategy):
      """Base class for implementing a partitioning strategy for a range
      partitioned table."""
  
  
  __all__ = ["PostgresRangePartitioningStrategy"]
  
subject: Fix #149: PostgresRangePartitioningStrategy should derive from PostgresPartitioningStrategy