fix function call

Author: adeas31

OMPython/ModelicaSystem.py

@@ -1078,7 +1078,7 @@ def simulate_cmd(
             # see https://github.com/OpenModelica/OpenModelica/pull/14813
             version = self._session.sendExpression("getVersion()", parsed=True)
             print(f"OpenModelica version string: {version}")
-            major, minor, patch = parse_om_version(version)
+            major, minor, patch = self.parse_om_version(version)
             if (major, minor, patch) > (1, 25, 0):
                 print("Version > 1.25.0")
                 for key, opt_value in self._simulate_options_override.items():