Enable multiple relation labels `(a)-[r:TYPE1|TYPE2]->(b)` in builder

[AntonLydike]

As per documentation you can supply the explicit relationship traversal settings with relation_type of None|*|<name>:

definition = dict(node_class=Person, direction=OUTGOING,
                 relation_type=None, model=None)
relations_traversal = Traversal(jim, Person.__label__,
                               definition)
all_jims_relations = relations_traversal.all()

The defintion argument is a mapping with these items:

node_class	The class of the traversal target node.
direction	match.OUTGOING / match.INCOMING / match.EITHER
relation_type	Can be None (for any direction), * for all paths or an explicit name of a relation type (the edge’s label).
model	The class of the relation model, None for such without one.

My suggestion is to extends this to include a list of names. This would result in a query using the (a)-[:TYPE1|TYPE2]->(b) syntax described by the neo4j docs here. This neo4j feature is supported since at least version 3.5, so compatibility should be of no concern.

This would be an example usage:

definition = dict(node_class=Person, direction=INCOMING,
                  relation_type=('FATHER','MOTHER'), model=None)
relations_traversal = Traversal(jim, Person.__label__,
                                definition)
all_jims_children = relations_traversal.all()

I am currently working on a PR, feedback is appreciated.

[aanastasiou]

@AntonLydike I have not seen PRs yet but yes this would be great and I think fairly straightforward. The challenging bit might be instantiating and returning the right relationship type.

[AntonLydike]

I have linked PR #534, it seems like the build system is broken at the moment (as described in the PR). Instantiating relationship types is not the problem as the query only returns the connected nodes, not edges.

It seems like this repo is a little bit dead tho. No activity on my PR and Issue in more than a month. I am a little disapointed tbh.