code: def p_scalar_group(self, p):
          
          if len(p) == 2:
              p[0] = (str(p[1]),)
  
          if len(p) == 3:
              p[0] = p[1] + (str(p[2]),)
  
          if len(p) == 4:
              p[0] = p[1] + (str(p[3]),)
docs: scalar_group    : SCALAR
                          | scalar_group SCALAR