docstr: ...Test HawkesKernelExp string in list representation
          
code: def test_HawkesKernelExp_repr(self):
      """...Test HawkesKernelExp string in list representation"""
      intensity = 3
      decay = 2
      hawkes_kernel_exp = HawkesKernelExp(intensity, decay)
      self.assertEqual(str([hawkes_kernel_exp]), "[3*2*exp(-2*t)]")
  
      intensity = 3
      decay = 0
      hawkes_kernel_exp = HawkesKernelExp(intensity, decay)
      self.assertEqual(str([hawkes_kernel_exp]), "[3]")
  
      intensity = 0
      decay = 2
      hawkes_kernel_exp = HawkesKernelExp(intensity, decay)
      self.assertEqual(str([hawkes_kernel_exp]), "[0]")
  
file_path: tick/tick/hawkes/simulation/tests/hawkes_kernel_exp_test.py
imports: import unittest
  from tick.hawkes import HawkesKernelExp
label_desc: Use image node_id 5 for calling the Test obj's underlying member method code with example usage: obj.test_HawkesKernelExp_repr() without return types