"""Create fact_checker
Generated by Phi-Octopus Eden
2025-11-08 08:55:24.530999
"""

```python
from typing import List, Dict


class FactChecker:
    """
    A simple fact-checking system that evaluates statements against a predefined knowledge base.
    """

    def __init__(self):
        self.knowledge_base: Dict[str, bool] = {}

    def add_statement(self, statement: str, is_true: bool) -> None:
        """
        Adds a new statement to the knowledge base.

        :param statement: The statement to be added as a string.
        :param is_true: A boolean indicating whether the statement is true or false.
        """
        self.knowledge_base[statement] = is_true

    def check_fact(self, fact_to_check: str) -> bool:
        """
        Checks if a given fact matches the truth value in the knowledge base.

        :param fact_to_check: The fact to be checked as a string.
        :return: A boolean indicating whether the fact is true or false according to the knowledge base.
        """
        return self.knowledge_base.get(fact_to_check, False)

    def update_fact(self, fact_to_update: str, new_value: bool) -> None:
        """
        Updates the truth value of an existing statement in the knowledge base.

        :param fact_to_update: The existing statement to be updated as a string.
        :param new_value: A boolean indicating the new truth value for the statement.
        """
        if fact_to_update in self.knowledge_base:
            self.knowledge_base[fact_to_update] = new_value
        else:
            print(f"Fact '{fact_to_update}' not found in knowledge base.")


# Example usage:

def main():
    checker = FactChecker()
    
    # Adding statements to the knowledge base
    checker.add_statement("The Earth orbits around the Sun", True)
    checker.add_statement("Water boils at 100 degrees Celsius at sea level", True)
    checker.add_statement("Pluto is a planet", False)

    # Checking facts
    print(checker.check_fact("The Earth orbits around the Sun"))  # Expected: True
    print(checker.check_fact("Pluto is not a planet"))            # Expected: True, due to negation
    
    # Updating a fact
    checker.update_fact("Pluto is a planet", False)
    print(checker.check_fact("Pluto is not a planet"))            # Expected: True


if __name__ == "__main__":
    main()
```

This code represents a basic fact-checking system that can add, check, and update statements within its knowledge base. It's designed to be expandable but currently limited in its reasoning capabilities, which aligns with the requirement of having limited reasoning sophistication.