Merge pull request #364 from PyPSA/xpress-writesol

xpress: writesol instead of tofile

Author: FabianHofmann

linopy/solvers.py

@@ -1472,7 +1472,7 @@ def solve_problem_from_file(
         if solution_fn is not None:
             try:
                 # TODO: possibly update saving of solution file
-                m.tofile(path_to_string(solution_fn), filetype="sol")
+                m.writesol(path_to_string(solution_fn))
             except Exception as err:
                 logger.info("Unable to save solution file. Raised error: %s", err)