Bug in get_rank method of Hyperedge View

[devendragovil]

What

There were a couple of bugs w.r.t get_rank method in Hyperedge View.

Details

The relevant code is present below

    def get_rank(self, e):
        """Get rank.

        Parameters
        ----------
        e : Iterable, Hashable or HyperEdge

        Returns
        -------
        int, the rank of the hyperedge e
        """
        if isinstance(e, Iterable):
            if len(e) == 0:
                return 0
            else:
                for i in list(self.allranks):
                    if frozenset(e) in self.hyperedge_dict[i]:
                        return i
                raise KeyError(f"hyperedge {e} is not in the complex")

        elif isinstance(e, HyperEdge):

            if len(e) == 0:
                return 0
            else:
                for i in list(self.allranks):

                    if frozenset(e.elements) in self.hyperedge_dict[i]:
                        return i
                raise KeyError(f"hyperedge {e} is not in the complex")

        elif isinstance(e, Hashable) and not isinstance(e, Iterable):

            if e in self.hyperedge_dict[0]:
                return 0
            else:
                raise KeyError(f"hyperedge {e} is not in the complex")

        elif isinstance(e, str):

            if e in self.hyperedge_dict[0]:
                return 0
            else:
                raise KeyError(f"hyperedge {e} is not in the complex")

Bugs

1. The hyperedge case in the above if-else block is never triggered because hyperedge itself is Iterable.
2. The str case in the above if-else block is never triggered because str itself is Iterable.
3. The cases where e is int or str never evaluates to True, because the int/str are not present in hyperedge_dict, but rather frozenset({e}) is

[mhajij]

please open a pull request and fix the above errors