Loads a MOL file of the ligand (submitted by user) into RDKit environment.
            Takes:
                * mol_file * - user submitted MOL file of the ligand
            Output:
                * self.mol_mda * - the ligand as MDAnalysis Universe,
                * self.mol * - the ligand in RDKit environment as Mol object.

def load_mol(self, mol_file):
        """Loads a MOL file of the ligand (submitted by user) into RDKit environment.
            Takes:
                * mol_file * - user submitted MOL file of the ligand
            Output:
                * self.mol_mda * - the ligand as MDAnalysis Universe,
                * self.mol * - the ligand in RDKit environment as Mol object.
        """
        #Check if MOL file has been provided correctly and can be loaded in MDAnalysis
        if mol_file is None:
            mol_file = "lig.mol"

        self.mol = Chem.MolFromMolFile(mol_file,removeHs=False,sanitize=False)
        try:
            self.mol.UpdatePropertyCache(strict=False)
        except AttributeError:
            assert self.mol != None, "The MOL file could not be imported in RDKit environment. Suggestion: Check the atomtypes."
        assert self.mol != None, "The MOL file could not be imported in RDKit environment."