"""Create fallback_executor
Generated by Phi-Octopus Eden
2025-11-08 12:32:11.310095
"""

```python
from typing import Callable, Any


class FallbackExecutor:
    """
    A class that provides functionality for executing tasks with fallbacks in case of errors.
    """

    def __init__(self):
        self._primary_executor: Callable = None
        self._fallback_executors: list[Callable] = []

    def set_primary_executor(self, executor: Callable) -> None:
        """
        Sets the primary executor function.

        :param executor: A callable object that is responsible for executing a task.
        """
        if not callable(executor):
            raise ValueError("The provided executor must be a callable object.")
        self._primary_executor = executor

    def add_fallback_executor(self, fallback_executor: Callable) -> None:
        """
        Adds a fallback executor function.

        :param fallback_executor: A callable object that is responsible for executing the task in case of an error
                                   with the primary executor.
        """
        if not callable(fallback_executor):
            raise ValueError("The provided fallback executor must be a callable object.")
        self._fallback_executors.append(fallback_executor)

    def execute(self, *args: Any, **kwargs: Any) -> Any:
        """
        Executes the task using the primary executor. If an error occurs during execution,
        attempts to use one of the fallback executors.

        :param args: Positional arguments passed to the primary and fallback executors.
        :param kwargs: Keyword arguments passed to the primary and fallback executors.
        :return: The result of the successful execution or None if all fallbacks fail.
        """
        try:
            return self._primary_executor(*args, **kwargs)
        except Exception as e:
            print(f"Primary executor failed with error: {e}")
            for fallback in self._fallback_executors:
                try:
                    return fallback(*args, **kwargs)
                except Exception as f_e:
                    print(f"Fallback executor failed with error: {f_e}")
                    continue
        return None


# Example usage:

def primary_task(a: int, b: int) -> int:
    """A function that adds two numbers."""
    return a + b

def fallback_1(a: int, b: int) -> int:
    """A simple fallback addition with some error handling."""
    try:
        return a + b
    except Exception as e:
        print(f"Fallback 1 failed with error: {e}")
        raise

def fallback_2(a: int, b: int) -> int:
    """Another fallback addition method."""
    try:
        return a - b
    except Exception as e:
        print(f"Fallback 2 failed with error: {e}")
        raise


executor = FallbackExecutor()
executor.set_primary_executor(primary_task)
executor.add_fallback_executor(fallback_1)
executor.add_fallback_executor(fallback_2)

# Successful execution
result = executor.execute(5, 3)  # Should return 8
print(result)

# Error in primary and fallbacks, all should fail
result = executor.execute('a', 'b')  # Should print errors and return None
print(result)
```

This code defines a `FallbackExecutor` class that allows for executing tasks with the possibility of using fallbacks when the primary execution fails. The example usage demonstrates how to set up and use this capability, including handling potential issues with different types of arguments.