You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: TS29512NpcfSMPolicyControlServer.gen.go
    path of file: ./repos/magma/feg/gateway/sbi/specs/TS29512NpcfSMPolicyControlServer
    
    the code of the file until where you have to start completion: // Package TS29512NpcfSMPolicyControlServer provides primitives to interact with the openapi HTTP API.
//
// Code generated by github.com/deepmap/oapi-codegen version v1.9.0 DO NOT EDIT.
package TS29512Np
    
func (a *SmPolicyDecision_PraInfos) UnmarshalJSON(b []byte) error {
	object := make(map[string]json.RawMessage)
	err := json.Unmarshal(b, &object)
	if err != nil {
		return err
	}

	if len(object) != 0 {
		a.AdditionalProperties = make(map[string]externalRef4.PresenceInfoRm)
		for fieldName, fieldBuf := range object {
			var fieldVal externalRef4.PresenceInfoRm
			err := json.Unmarshal(fieldBuf, &fieldVal)
			if err != nil {
				return fmt.Errorf("error unmarshaling field %s: %w", fieldName, err)
			}
			a.AdditionalProperties[fieldName] = fieldVal
		}
	}
	return nil
}