strict property
Whether this graph is in strict mode.
https://graphviz.org/doc/info/lang.html#lexical-and-semantic-notes:
A graph may also be described as strict. This forbids the creation of multi-edges, i.e., there can be at most one edge with a given tail node and head node in the directed case. For undirected graphs, there can be at most one edge connected to the same two nodes. Subsequent edge statements using the same two nodes will identify the edge with the previously defined one and apply any attributes given in the edge statement.
Implementation
final bool strict;