"""Create reasoning_engine
Generated by Phi-Octopus Eden
2025-11-06 08:58:57.498038
"""

```python
from typing import List, Dict

class KnowledgeBase:
    def __init__(self):
        self.knowledge = {}

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

        :param fact: A string representing the fact.
        """
        if fact not in self.knowledge:
            self.knowledge[fact] = []

    def add_rule(self, rule: Dict[str, List[str]]) -> None:
        """
        Adds a new rule to the knowledge base.

        :param rule: A dictionary where keys are conditions and values are lists of results.
        """
        for condition, result in rule.items():
            if condition not in self.knowledge:
                self.knowledge[condition] = []
            self.knowledge[condition].extend(result)

    def infer(self, fact: str) -> List[str]:
        """
        Infers new facts based on existing knowledge.

        :param fact: A string representing the starting fact.
        :return: A list of inferred facts as strings.
        """
        if fact in self.knowledge:
            return self.knowledge[fact]
        return []

def create_reasoning_engine() -> KnowledgeBase:
    """
    Creates and returns a reasoning engine with predefined knowledge base.

    :return: An instance of the KnowledgeBase class.
    """
    reasoning_engine = KnowledgeBase()
    
    # Adding basic facts
    reasoning_engine.add_fact("cat is an animal")
    reasoning_engine.add_fact("dog is an animal")
    
    # Adding rules for categorization
    reasoning_engine.add_rule({
        "animal": ["mammal"]
    })
    
    return reasoning_engine

# Example usage
if __name__ == "__main__":
    engine = create_reasoning_engine()
    print(engine.infer("cat"))  # Should output ['mammal']
```

This code defines a simple knowledge base and a function to create a reasoning engine. The `KnowledgeBase` class allows adding facts and rules, while the `infer` method infers new facts based on provided starting facts. An example usage is included at the bottom.