docstr: ...Test that HawkesCumulantMatching raises an error if no data is
  given
docstr_tok: ["...","Test","that","HawkesCumulantMatching","raises","an","error","if","no","data","is","given"]
code: def test_hawkes_cumulants_unfit(self):
      """...Test that HawkesCumulantMatching raises an error if no data is
      given
      """
      learner = HawkesCumulantMatching(
          100.0,
          cs_ratio=0.9,
          max_iter=299,
          print_every=30,
          step=1e-2,
          solver="adam",
      )
  
      msg = "^Cannot compute cumulants if no realization has been provided$"
      with self.assertRaisesRegex(RuntimeError, msg):
          learner.compute_cumulants()
  
imports: import os
  import pickle
  import unittest
  import numpy
  from tick.base.inference import InferenceTest
  from tick.hawkes import HawkesCumulantMatching, HawkesCumulantMatchingTf, HawkesCumulantMatchingPyT
  from tick.hawkes.inference.hawkes_cumulant_matching import HawkesTheoreticalCumulant
label_desc: Use image node_id 5 for calling the Test obj's underlying member method code with example usage: obj.test_hawkes_cumulants_unfit() without return types