code: def round(self, value_array):
          
          distances = np.linalg.norm(np.array(self.domain) - value_array, axis=1)
          idx = np.argmin(distances)
          return [self.domain[idx]]
docs: Rounds a bandit variable by selecting the closest point in the domain
          Closest here is defined by euclidian distance
          Assumes an 1d array of the same length as the single variable value