Facing issue while verifying upload API in robot framework using python

I am very new to testing / developing. I am currently testing a REST API. In Postman I send a POST request by specifying parameters and uploading a file using form-data in the body. My request always succeeds. However, when I try to translate this into Robot Framework (using the Requests Library), I get a 400 Error.

I am posting my code below.

I have been trying to resolve this issue for a while now. Any help in the right direction would be much appreciated!

${base_URL}= https://someurl.com
${file_name}= Get Binary File Test.txt
*** Test Cases ***
#Verify that user able to upload the selected file using insertfile api
TC008_Upload_File
create session upload_file ${base_url}
${body}= create dictionary asset=${file_name}
${header}= create dictionary Content-Type=multipart/form-data:boundary=<calculated when request is sent> Accept=text/plain

${response}= post request upload_file /api/insertFile data=${body} headers=${header}
log to console ${response.content}
#to validate status code with the actual status code
${Status_code}= convert to string ${response.status_code}
should be equal ${Status_code} 200

#to validate the content of the response body
${response_body}= convert to string ${response.content}
should contain ${response_body} true