def store(self, **kwargs):
        """
        Save something into the epoch_logger's current state.

        Provide an arbitrary number of keyword arguments with numerical 
        values.
        """
        for k,v in kwargs.items():
            if not(k in self.epoch_dict.keys()):
                self.epoch_dict[k] = []
            self.epoch_dict[k].append(v)

        Save something into the epoch_logger's current state.

        Provide an arbitrary number of keyword arguments with numerical 
        values.
        
spinup/utils/logx.py