Gurobi model object. Commonly used methods on the model object in the Gurobi shell include optimize (optimizes the model), printStats (prints statistics about the model), printAttr (prints the values of an attribute), and write (writes information about the model to a file). Commonly used methods when building a model include addVar (adds a new variable), addVars (adds multiple new variables), addConstr (adds a new constraint), and addConstrs (adds multiple new constraints).