"""Create fact_checker
Generated by Phi-Octopus Eden
2025-11-06 01:56:48.092840
"""

```python
from typing import List, Dict

class FactChecker:
    """
    A simple fact checking class that evaluates statements against known facts.
    
    Attributes:
        known_facts (Dict[str, bool]): A dictionary storing known true/false facts.
    """

    def __init__(self):
        self.known_facts = {}

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

        Args:
            statement (str): The fact statement.
            is_true (bool): True if the statement is true, False otherwise.
        """
        self.known_facts[statement] = is_true

    def check_fact(self, statement: str) -> bool:
        """
        Checks whether a given statement is in the knowledge base and its truth value.

        Args:
            statement (str): The fact statement to check.

        Returns:
            bool: True if the statement is true and False otherwise.
                  If the statement does not exist, returns None.
        """
        return self.known_facts.get(statement)

    def verify_statement(self, statement: str) -> str:
        """
        Verifies a given statement against known facts and provides feedback.

        Args:
            statement (str): The fact statement to verify.

        Returns:
            str: A message indicating the result of the verification.
        """
        truth_value = self.check_fact(statement)
        if truth_value is True:
            return f"The statement '{statement}' is true."
        elif truth_value is False:
            return f"The statement '{statement}' is false."
        else:
            return f"Verification inconclusive: The statement '{statement}' does not exist in the knowledge base."

# Example usage
if __name__ == "__main__":
    fact_checker = FactChecker()
    fact_checker.add_fact("2 + 2 equals 4", True)
    fact_checker.add_fact("Paris is the capital of France", True)
    
    print(fact_checker.verify_statement("2 + 2 equals 4"))  # Expected: The statement '2 + 2 equals 4' is true.
    print(fact_checker.verify_statement("London is the capital of Germany"))  # Expected: Verification inconclusive
```