On line 885 of hypergraph.py, the wrong constructor is used when resetting the nodes during the action of the clear_edges() method. The dict constructor ({}) is used when it should be the set constructor (set()). This means that an error is raised when trying to add edges back after clearing all edges.

Error raised: AttributeError: 'dict' object has no attribute 'add'

This can be rectified by replacing the {} with set() on line 885.