docstr: ...Test HawkesKernelSumExp latex string representation
          
code: def test_HawkesKernelSumExp_strtex(self):
      """...Test HawkesKernelSumExp latex string representation"""
      self.assertEqual(
          self.hawkes_kernel_sumexp.__strtex__(),
          "$0.3 e^{- t}$ + $8 e^{-2 t}$ + $0.4 e^{-0.2 t}$",
      )
  
file_path: tick/tick/hawkes/simulation/tests/hawkes_kernel_sum_exp_test.py
imports: import unittest
  import numpy
  from tick.hawkes import HawkesKernelSumExp
label_desc: Use image node_id 7 for calling the Test obj's underlying member method code with example usage: obj.test_HawkesKernelSumExp_strtex() without return types