docs: def p_expr_assign(p):
      '''expr : variable EQUALS expr
              | variable EQUALS AND expr'''
      if len(p) == 5:
          p[0] = ast.Assignment(p[1], p[4], True, lineno=p.lineno(2))
      else:
          p[0] = ast.Assignment(p[1], p[3], False, lineno=p.lineno(2))