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 __init__(self, name, op, num_val, nom_val):
      self.name = name
      self.op = op
      self.num_val = num_val
      self.nom_val = nom_val
  
imports: import numpy
  import numba
label_desc: Use image node_id 1 to create a new Literal object from inherited base classes: object with example: obj = Literal(name, op, num_val, nom_val)