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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 free_parameters(self):
 """ Get a dictionary with all the free parameters in this model :return: dictionary of free parameters """


        # Refresh the list

        self._update_parameters()

        # Filter selecting only free parameters

        free_parameters_dictionary = collections.OrderedDict()

        for parameter_name, parameter in self._parameters.iteritems():

            if parameter.free:

                free_parameters_dictionary[parameter_name] = parameter

        return free_parameters_dictionary