I have a request body json like this:

{ "id": "12345", "jsonrpc": "2.0", "method": "execute_kw", "context": {}, "params": { "args": [ "MyDb", 212, "123456789", "hr.expense", "upload_attachment_data_from_portal", [ 49061, { "filename": "image.jpg", "data": "my base64 satring" } ] ], "method": "execute_kw", "service": "object" }}

error: "arguments": ["'str' object has no attribute 'data'"]

however when I use xmlrpc it works with code like this

<methodCall>

<methodName>execute_kw</methodName>

<params>

<param>

<string>MyDb</string>

</param>

<param>

<int>22</int>

</param>

<param>

<string>123456789</string>

</param>

<param>

<string>hr.expense</string>

</param>

<param>

<string>upload_attachment_data_from_portal</string>

</param>

<param>

<array>

<int>49061</int>

<struct>

<member>

<name>filename</name>

<value>

<string>test.jpg</string>

</value>

</member>

<member>

<name>data</name>

<value>

<base64>my base64 string</base64>

</value>

</member>

</struct>

</array>

</param>

</params>

</methodCall>

```