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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def edge_to_bel(u: BaseEntity, v: BaseEntity, edge_data: EdgeData, sep: Optional[str] = None) -> str: """Serialize a pair of nodes and related edge data as a BEL relation."""

        return edge_to_bel(u, v, data=edge_data, sep=sep)