class RelationshipIdentifier:
    """Identifies relationships between nodes in a graph database."""

    RELATIONSHIP_EXAMPLE = [
        ("NodeLabel1", "RelationshipLabel", "NodeLabel2"),
        ("NodeLabel1", "RelationshipLabel", "NodeLabel3"),
        ("NodeLabel2", "RelationshipLabel", "NodeLabel3"),
    ]

    PROMPT_TEMPLATE = PromptTemplate(
    input_variables=["structure", "node_definitions", "example"],
    template="""
        Consider the following Dataset Structure:n{structure}nn

        Consider the following Node Definitions:n{node_definitions}nn

        Based on the dataset structure and node definitions, identify relationships (edges) between nodes.n
        Return the relationships as a list of triples where each triple contains the start node label, relationship label, and end node label, and each triple is a tuple.n
        Please return only the list of tuples. Please do not report triple backticks to identify a code block, just return the list of tuples.nn

        Example:n{example}
        """
)

    def __init__(self, llm: Any, logger: logging.Logger = None):
        self.llm = llm
        self.logger = logger or logging.getLogger(__name__)
        self.chain = self.PROMPT_TEMPLATE | self.llm

    def validate_relationships(self, relationships: List[Tuple]) -> bool:
        """Validate relationship structure."""
        return all(
            isinstance(rel, tuple) and 
            len(rel) == 3 and 
            all(isinstance(x, str) for x in rel)
            for rel in relationships
        )

    @retry(stop=stop_after_attempt(3), wait=wait_exponential(multiplier=1, min=4, max=10))
    def identify_relationships(self, structure: str, node_definitions: Dict) -> List[Tuple]:
        """Identify relationships with retry logic."""
        try:
            response = self.chain.invoke({
                "structure": structure, 
                "node_definitions": str(node_definitions), 
                "example": str(self.RELATIONSHIP_EXAMPLE)
            })

            relationships = ast.literal_eval(response)

            if not self.validate_relationships(relationships):
                raise ValueError("Invalid relationship structure")

            self.logger.info(f"Identified {len(relationships)} relationships")
            return relationships

        except Exception as e:
            self.logger.error(f"Error identifying relationships: {e}")
            raise

    def get_relationship_types(self) -> List[str]:
        """Extract unique relationship types."""
        return list(set(rel[1] for rel in self.identify_relationships()))

# Usage
identifier = RelationshipIdentifier(llm=llm)
relationships = identifier.identify_relationships(node_structure, node_definitions)
print("Relationships:", relationships)