marshmallow-sqlalchemy给出语法错误

Question

在Python3.5中安装marshmallow-sqlalchemy后，它显示语法错误。

我使用下面的命令pip install marshmallow-sqlalchemy安装了它。

Traceback (most recent call last):
  File "run.py", line 1, in <module>
    from app import flask_app
  File "/var/www/html/mswipe-banner/mswipe-banner/app/__init__.py", line 10, in <module>
    from .models import *
  File "/var/www/html/mswipe-banner/mswipe-banner/app/models/__init__.py", line 1, in <module>
    from .banner import *
  File "/var/www/html/mswipe-banner/mswipe-banner/app/models/banner.py", line 1, in <module>
    from .base_model import *
  File "/var/www/html/mswipe-banner/mswipe-banner/app/models/base_model.py", line 1, in <module>
    from flask_marshmallow import Marshmallow
  File "/var/www/html/mswipe-banner/lib/python3.5/site-packages/flask_marshmallow/__init__.py", line 24, in <module>
    from . import sqla
  File "/var/www/html/mswipe-banner/lib/python3.5/site-packages/flask_marshmallow/sqla.py", line 13, in <module>
    import marshmallow_sqlalchemy as msqla
  File "/var/www/html/mswipe-banner/lib/python3.5/site-packages/marshmallow_sqlalchemy/__init__.py", line 1, in <module>
    from .schema import TableSchemaOpts, ModelSchemaOpts, TableSchema, ModelSchema
  File "/var/www/html/mswipe-banner/lib/python3.5/site-packages/marshmallow_sqlalchemy/schema.py", line 3, in <module>
    from .convert import ModelConverter
  File "/var/www/html/mswipe-banner/lib/python3.5/site-packages/marshmallow_sqlalchemy/convert.py", line 80
    ):
    ^
SyntaxError: invalid syntax

谢谢你，?

Answer 1

安装失败，因为marshmallow-sqlalchemy no longer supports Python3.5。支持Python3.5的最后一个版本是18.0版，必须显式安装。

回溯中的特定错误是由this函数声明引起的：

def fields_for_model(
    self,
    model,
    *,
    include_fk=False,
    fields=None,
    exclude=None,
    base_fields=None,
    dict_cls=dict,
):

Python3.6包含一个允许在函数参数列表中使用尾随逗号的change。在此更改之前，这些签名是合法的：

>>> def f(a, b, c=1,):pass
... 
>>> def f(a, b, *, c=1):pass
... 
>>>

但这并不是

>>> def f(a, b, *, c=1,):pass
  File "<stdin>", line 1
    def f(a, b, *, c=1,):pass
                       ^
SyntaxError: invalid syntax

参数列表中间的* -指示仅关键字参数的开始-在版本18之后被添加到上面的marshmallow-sqlalchemy函数签名中，作为降低2.7和3.5兼容性的过程的一部分。