Python执行web接口测试用例时，POST请求返回报文报“{"msg":"JSON parse error: Cannot construct instance of `xxxxx` }

使用Python+unittest完成web接口测试用例，调用post方法是，一直返回错误报文：

{"msg":"JSON parse error: Cannot construct instance of `xxxxx` (although at least one Creator exists): no String-argument constructor/factory method to deserialize from String value (''); nested exception is com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot construct instance of `xxxxx` (although at least one Creator exists): no String-argument constructor/factory method to deserialize from String value ('') at [Source: (PushbackInputStream); line: 1, column: 1]","code":500,"data":null

纠结了很久，网上也查询了，也请教了Java开发，结果发现是post请求的参数写错导致，心中顿时几千万个那什么呼啸而过，这个问题的原因也太简单了，也是因为自己对各个请求方法的传参不够熟练导致（但是这个错误提示也够奇葩的，直接提示我参数传递错误就行呀。。。）

错误的请求样例：

正确的请求样例：