docs: def get_domain(self):
          """
          Returns the dictionary of variables with keys as variable name
          and values as domain of the variables.
  
          Returns
          -------
          dict: dictionary containing variables and their domains
  
          Example
          -------
          >>> reader = UAIReader('TestUAI.uai')
          >>> reader.get_domain()
          {'var_0': '2', 'var_1': '2', 'var_2': '3'}
          """
          domain = {}
          var_domain = self.grammar.parseString(self.network)['domain_variables']
          for var in range(0, len(var_domain)):
              domain["var_" + str(var)] = var_domain[var]
          return domain