"""Create fact_checker
Generated by Phi-Octopus Eden
2025-11-06 15:00:56.301425
"""

```python
from typing import List, Dict

class FactChecker:
    """
    A basic fact-checking tool that verifies if a statement is true or false based on predefined facts.
    """

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

    def add_fact(self, statement: str, truth_value: bool) -> None:
        """
        Adds a new fact to the checker.

        :param statement: The fact in string form (e.g., "The Earth is round")
        :param truth_value: True if the statement is true, False otherwise
        """
        self.facts[statement] = truth_value

    def check_fact(self, statement: str) -> bool:
        """
        Checks if a given statement is supported by the current set of facts.

        :param statement: The fact to be checked
        :return: True if the statement matches an existing true fact or no conflicting facts exist, False otherwise
        """
        return self.facts.get(statement, False)

    def are_facts_consistent(self) -> bool:
        """
        Verifies that all the added facts do not contradict each other.

        :return: True if there are no contradictions among the facts, False otherwise
        """
        unique_statements = set()
        for fact in self.facts.values():
            if fact:
                unique_statements.add(True)
            else:
                unique_statements.add(False)

        return len(unique_statements) == 1

# Example usage:

def main():
    checker = FactChecker()
    
    # Adding facts
    checker.add_fact("The Earth is round", True)
    checker.add_fact("2 + 2 equals 5", False)
    checker.add_fact("Water boils at 100 degrees Celsius", True)

    print(f"Checking 'The Earth is round': {checker.check_fact('The Earth is round')}")  # Should be True
    print(f"Checking '2 + 2 equals 4': {checker.check_fact('2 + 2 equals 4')}")  # Should raise KeyError as not added

    # Verifying consistency
    print(f"Facts are consistent: {checker.are_facts_consistent()}")  # Should be False due to contradiction in the second fact

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