FormGraph.edge_attribute
- FormGraph.edge_attribute(key, name, value=None)[source]
 Get or set an attribute of an edge.
- Parameters
 key (tuple[hashable, hashable]) – The identifier of the edge as a pair of node identifiers.
name (str) – The name of the attribute.
value (obj, optional) – The value of the attribute.
- Returns
 object | None – The value of the attribute, or None when the function is used as a “setter”.
- Raises
 KeyError – If the edge does not exist.