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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 _flatten_obs(self, obs_dict, verbose=False):
 """ Filters keys of interest out and concatenate the information. Args: obs_dict: ordered dictionary of observations """

        ob_lst = []
        for key in obs_dict:
            if key in self.keys:
                if verbose:
                    print("adding key: {}".format(key))
                ob_lst.append(obs_dict[key])
        return np.concatenate(ob_lst)