@brief Get a graph

`graph_module._graph(graphName)`

A graph can be retrieved by its name.

@PARAMS

@PARAM{graphName, string, required}
Unique identifier of the graph

@EXAMPLES

Get a graph:

@EXAMPLE_ARANGOSH_OUTPUT{generalGraphLoadGraph}
~ var examples = require("@arangodb/graph-examples/example-graph.js");
~ var g1 = examples.loadGraph("social");
  var graph_module = require("@arangodb/general-graph");
  graph = graph_module._graph("social");
~ examples.dropGraph("social");
@END_EXAMPLE_ARANGOSH_OUTPUT