Google Drive API adding some string in file

Question

I have been trying to replace files using google API only with the Python HTTPS module. But when I replace it. It adds some string to the file with text. Code:

headers = {
        "Authorization": "Bearer " + str(Acesstoken),
    }

files = {  
    'file': open("./Test.txt", "rb"),
    "mimeType": "text/plain"
    }


r2= requests.patch(
    "https://www.googleapis.com/upload/drive/v3/files/" + updateFileId,
    headers= headers,
    files = files,
)

Text On Google Drive Before Replacing File:

Test

Text On Google Drive After Replacing File:

--a164a6e367e3577590ab9eb85b487e21
Content-Disposition: form-data; name="file"; filename="Test.txt"

Test 2
--a164a6e367e3577590ab9eb85b487e21
Content-Disposition: form-data; name="mimeType"; filename="mimeType"

text/plain
--a164a6e367e3577590ab9eb85b487e21--

Advance Thanks to @DaImTo

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