"""Create recovery_planner
Generated by Phi-Octopus Eden
2025-11-08 20:42:41.254907
"""

```python
from typing import Dict, Any, List

class RecoveryPlanner:
    """
    A class designed to handle limited error recovery in a system.
    
    This class is responsible for managing error recovery strategies and providing methods to
    assess and mitigate errors based on predefined rules.

    Attributes:
        error_strategies (Dict[str, Any]): A dictionary containing the error recovery strategies.
        current_state (List[str]): A list indicating the current state of the system.
    """
    
    def __init__(self):
        self.error_strategies = {
            "network_failure": {"timeout": 5, "retry_count": 3},
            "data_corruption": {"recovery_function": lambda x: self._repair_data(x)},
            "unhandled_exception": {"log_and_exit": True}
        }
        self.current_state = []

    def assess_error(self, error_type: str) -> bool:
        """
        Assess if the given error type is in the current state.
        
        Args:
            error_type (str): The type of error to assess.
            
        Returns:
            bool: True if the error type is present in the current state, False otherwise.
        """
        return error_type in self.current_state

    def apply_recovery_strategy(self, error_type: str) -> Any:
        """
        Apply the recovery strategy for the given error type.
        
        Args:
            error_type (str): The type of error to handle.
            
        Returns:
            Any: The result of applying the recovery strategy or None if no strategy is defined.
        """
        return self.error_strategies.get(error_type, {}).get("recovery_function", lambda x: None)(error_type)

    def _repair_data(self, error_type: str) -> str:
        """
        A private function to simulate data repair logic.
        
        Args:
            error_type (str): The type of error indicating which data needs repair.
            
        Returns:
            str: A message indicating the outcome of the repair operation.
        """
        return f"Data corruption recovered for {error_type}"

    def add_state(self, state: str) -> None:
        """
        Add a new state to the current system state list.
        
        Args:
            state (str): The new state to add to the current state list.
        """
        self.current_state.append(state)

def example_usage():
    planner = RecoveryPlanner()
    
    # Simulate network failure
    planner.add_state("network_failure")
    
    print("Current state:", planner.current_state)
    
    if planner.assess_error("network_failure"):
        result = planner.apply_recovery_strategy("network_failure")
        print("Recovery strategy applied:", result)

example_usage()
```

This Python script demonstrates a basic implementation of an error recovery planner with the specified functionality and requirements. The `RecoveryPlanner` class includes methods for assessing errors, applying recovery strategies, and managing system states. The example usage illustrates how to use this class in practice.