swagger-py-codegen : TypeError: generate() got an unexpected keyword argument 'spec'

是因為版本的關係

ERROR: pip's dependency resolver does not currently take into account all the packages that are installed. 
This behaviour is the source of the following dependency conflicts.
swagger-py-codegen 0.4.0 requires click<7, but you have click 8.0.3 which is incompatible.
connexion 2.10.0 requires PyYAML<6,>=5.1, but you have pyyaml 4.2b1 which is incompatible.

但是 flask 又要 >7，所以 swagger-py-codegen 跟 flask 沒有板法一起。
只好用 conda create 兩個 env

不然，swagger-py-codegen 使用click 8.0.3 的話，會說 --spec 這個參數不認識。