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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def dir_(self):
 """The prefered way for HydPy objects to respond to |dir|. Note the depencence on the `pub.options.dirverbose`. If this option is set `True`, all attributes and methods of the given instance and its class (including those inherited from the parent classes) are returned: True If the option is set to `False`, only the `public` attributes and methods (which do need begin with `_`) are returned: ['only_public_attribute'] If none of those does exists, |dir_| returns a list with a single string containing a single empty space (which seems to work better for most IDEs than returning an emtpy list):
 [' '] """

    names = set()
    for thing in list(inspect.getmro(type(self))) + [self]:
        for key in vars(thing).keys():
            if hydpy.pub.options.dirverbose or not key.startswith('_'):
                names.add(key)
    if names:
        names = list(names)
    else:
        names = [' ']
    return names