Multi-edges between two nodes

Hello, I use the new version 0.5.1 of grand-graph:

```python
from grand import Graph
from grandcypher import GrandCypher
from grand.backends._sqlbackend import SQLBackend

backend=SQLBackend(db_url="sqlite:///demo2.db")
G = Graph(backend=backend)

G.nx.add_node("spranger", type="Person")
G.nx.add_node("meier", type="Person")
G.nx.add_node("krause", type="Person")
G.nx.add_node("Berlin", type="City")
G.nx.add_node("Paris", type="City")
G.nx.add_node("London", type="City")

G.nx.add_edge("spranger", "Paris", type="LIVES_IN")
G.nx.add_edge("krause", "Berlin", type="LIVES_IN")
G.nx.add_edge("meier", "London", type="LIVES_IN")
G.nx.add_edge("spranger", "Berlin", type="BORN_IN")
G.nx.add_edge("krause", "Berlin", type="BORN_IN")
G.nx.add_edge("meier", "Berlin", type="BORN_IN")

result1 = GrandCypher(G.nx).run("""
MATCH (n)-[r]->(c)
WHERE
n.type == "Person"
and
c.type == "City"

RETURN n, r, c
""")

from lark.lexer import Token
n = result1[Token('CNAME', 'n')]
r = result1[Token('CNAME', 'r')]
c = result1[Token('CNAME', 'c')]

for i in range(len(n)):
print(f"{n[i]} - {r[i].get('type')} -> {c[i]}")

backend.commit()
backend.close()
```

results in

- spranger - BORN_IN -> Berlin
- spranger - LIVES_IN -> Paris
- meier - BORN_IN -> Berlin
- meier - LIVES_IN -> London
- krause - BORN_IN -> Berlin-

1. The "krause - LIVES_IN -> Berlin" relation is not stored (as any second relation between two same nodes) .
This might be due to the cause that our "G.nx" doesn't cope with multigraphs.
2. In plain grandcypher I can query "Match (p:Person)" . How do I do this in my cypher query above?
3. Would it be a good idea to have the backend and the graph layer (e.g. netwrokx) completely transparent and just run Cypher queries, also for creating nodes and relations?

Kind Regards.
Steffen, the graphologist