code: def p_array_index(self, p):
          '''array_index :
                         | NUM
                         | COLUMN
                         | COLUMN COLUMN'''
          if len(p) == 3:
              p[0] = slice(0, -1, -1)
          elif len(p) == 1 or p[1] == ':':
              p[0] = slice(0, -1, 1)
          else:
              p[0] = slice(0, int(p[1]), 1f p_array_index(self, p):
          '''array_index :
                         | NUM
                         | COLUMN
                         | COLUMN COLUMN'''
          if len(p) == 3:
              p[0] = slice(0, -1, -1)
          elif len(p) == 1 or p[1] == ':':
              p[0] = slice(0, -1, 1)
          else:
              p[0] = slice(0, int(p[1]), 1)
docs: array_index :
                         | NUM
                         | COLUMN
                         | COLUMN COLUMN