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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 expand(self, *args, **kwargs):
 """Expands the template with the given data dictionary, returning a string. This is a small wrapper around execute(), and is the most convenient interface. Args: data_dict: The JSON data dictionary. Like the builtin dict() constructor, it can take a single dictionary as a positional argument, or arbitrary keyword arguments. trace: Trace object for debugging style: Template instance to be treated as a style for this template (the "outside") Returns: The return value could be a str() or unicode() instance, depending on the the type of the template string passed in, and what the types the strings in the dictionary are. """

        if args:
            if len(args) == 1:
                data_dict = args[0]
                trace = kwargs.get('trace')
                style = kwargs.get('style')
            else:
                raise TypeError(
                    'expand() only takes 1 positional argument (got %s)' % args)
        else:
            data_dict = kwargs
            trace = None  # Can't use trace= with the kwargs style
            style = None
        
        tokens = []
        group = _MakeGroupFromRootSection(self._program, self.undefined_str)
        if style:
            style.execute(data_dict, tokens.append, group=group,
                          trace=trace)
        else:
            # Needs a group to reference its OWN {.define}s
            self.execute(data_dict, tokens.append, group=group,
                         trace=trace)
        
        return JoinTokens(tokens)