How to use the f90wrap.fortran.walk_modules function in f90wrap

def fix_element_uses_clauses(tree, types):
    """
    Add uses clauses to derived type elements in modules
    """
    for mod in ft.walk_modules(tree):
        for el in mod.elements:
            el.uses = set()
            if el.type.startswith('type') and ft.strip_type(el.type) in types:
                el.uses.add((types[el.type].mod_name, (ft.strip_type(el.type),)))

    return tree

initial modules to search, must be included in the tree.

    tree : `fortran.Root()` object.
        the full fortran parse tree from which the mods have been taken.

    Returns
    -------
    all_mods : set
        Module() objects which are recursively used by the given modules.
    """
    new_mods = copy.copy(mods)
    while new_mods != set():
        temp = list(new_mods)
        for m in temp:
            for m2 in m.uses:
                for m3 in ft.walk_modules(tree):
                    if m3.name == m2:
                        new_mods.add(m3)
        new_mods -= mods
        mods |= new_mods

    return mods

Returns
    -------
    kept_types : set of Type() objects which are referenced or defined in the
                 modules given, or recursively referenced by those types.
    """

    # Get used types now
    kept_types = set()
    for mod in mods:
        for t in mod.types:
            kept_types.add(t)

        for el in mod.elements:
            if el.type.startswith('type'):
                for mod2 in ft.walk_modules(tree):
                    for mt in mod2.types:
                        if mt.name in el.type:
                            kept_types.add(mt)

    # kept_types is now all types defined/referenced directly in kept_mods. But we also
    # need those referenced by them.
    new_set = copy.copy(kept_types)
    while new_set != set():
        temp_set = list(new_set)
        for t in temp_set:
            for el in t.elements:
                if el.type.startswith('type'):  # a referenced type, need to find def
                    for mod2 in ft.walk_modules(tree):
                        for mt in mod2.types:
                            if mt.name in el.type:
                                new_set.add(mt)