class_docstr: A literal is an atomic formula (atom). In rule induction, the negation of an atom needs
  to be explicitly added. For example, ‘credit score >= 200’ and ‘credit score < 200’ (to solve
  some issues related to float number, the complement of >= is sometimes written as <=) need to
  be added at the same time
  
  name : int64_t
      Feature name for literal (encoded)
  op : uint8_t
      Operator for literal (encoded)
  num_val : double
      Numerical feature value for literal (encoded)
  nom_val : int64_t
      Nominal feature value for literal
code: def __str__(self):
      return self.__repr__()
  
imports: import numpy
  import numba
label_desc: Use image node_id 3 for calling the Literal obj's underlying member method code with example usage: obj.__str__() and returns: self