pub trait SolverWithSolutionParsing {
// Required method
fn read_specific_solution<'a>(
&self,
f: &File,
problem: Option<&'a LpProblem>,
) -> Result<Solution<'a>, String>;
// Provided method
fn read_solution<'a>(
&self,
temp_solution_file: &String,
problem: Option<&'a LpProblem>,
) -> Result<Solution<'a>, String> { ... }
}