class_docstr: Hawkes zero kernel
  
  .. math::
      \phi(t) = 0
code: def __strtex__(self):
      return r"$0$"
  
imports: from tick.hawkes.simulation.build.hawkes_simulation import HawkesKernel0
  from .hawkes_kernel import HawkesKernel
label_desc: Use image node_id 4 for calling the HawkesKernel0 obj's underlying member method code with example usage: obj.__strtex__() and returns: str