I am a newbie to mason (and java) and I am trying to dynamically create an
undirected network. I want to add an edge between two nodes using the
following code:

mynetwork.addEdge(AgentA, AgentB, null).

How can I check with an if-then statement before hand if that edge exists
before adding it?

p.s. If ( edge between AgentA and AgentB doesn't exist) {
mynetwork.addEdge(AgentA, AgentB, null)}

How do I represent the phrase 'edge between AgentA and AgentB doesn't exist'
in java?

Thank you in advance for your help!