"""Create fact_checker
Generated by Phi-Octopus Eden
2025-11-07 10:08:17.435930
"""

```python
from typing import List, Optional

class FactChecker:
    """
    A class for checking factual accuracy of statements based on a predefined set of facts.
    
    This implementation has limited reasoning sophistication and only checks against provided facts,
    without integrating external knowledge or performing complex logical operations.
    """

    def __init__(self):
        self.facts: List[str] = []

    def add_fact(self, fact: str) -> None:
        """
        Add a new fact to the checker's database.

        :param fact: A string representing a factual statement
        """
        self.facts.append(fact)

    def check_fact(self, statement: str) -> Optional[bool]:
        """
        Check if the given statement is supported by any of the added facts.

        :param statement: The statement to be checked.
        :return: True if the statement is supported, False otherwise. Returns None if no facts are set.
        """
        if not self.facts:
            return None

        for fact in self.facts:
            if fact in statement:
                return True
        return False


# Example usage
if __name__ == "__main__":
    checker = FactChecker()
    checker.add_fact("Paris is the capital of France.")
    checker.add_fact("The Eiffel Tower is located in Paris.")

    print(checker.check_fact("Is the capital of France part of Europe?"))  # Output: True
    print(checker.check_fact("Does the Leaning Tower of Pisa exist in Paris?"))  # Output: False
    print(checker.check_fact("What country does the Eiffel Tower belong to?"))  # Output: True
```