title: etsy-api-oauth1 PUT Requests return invalid signature when made from python, but not from Postman
body: <p>I've been troubleshooting an issue when sending a PUT Request to the ETSY REST API,
  when I make a PUT request, I get a <code>signature invalid error</code>. I have tried all the solutions found on google, but none seem to work.</p>
  
  <p>Sending the same request through POSTMAN works, if I specify the auth parameters to go in the body. However when I try to replicate this using python's standard procedures I get the same <code>invalid signature error</code>.</p>
  
  <p>Even if I export the python code for that exact request from postman, I get a signature invalid error when running said code in python. </p>
  
  <p>This is the json data I need to send:</p>
  
  <pre><code>"products": [
        {
           "product_id":4262200422,
           "sku":"00100012",
           "property_values":[
              {
                 "property_id":200,
                 "property_name":"Primary color",
                 "scale_id":null,
                 "scale_name":null,
                 "values":[
                    "Black"
                 ],
                 "value_ids":[
                    1
                 ]
              }
           ],
           "offerings":[
              {
                 "offering_id":4128359213,
                 "price":{
                    "amount":200,
                    "divisor":100,
                    "currency_code":"GBP",
                    "currency_formatted_short":"\\u00a32.00",
                    "currency_formatted_long":"\\u00a32.00 GBP",
                    "currency_formatted_raw":"2.00"
                 },
                 "quantity":12,
                 "is_enabled":1,
                 "is_deleted":0
              }
           ],
           "is_deleted":0
        },
        {
           "product_id":4031391357,
           "sku":"00100013",
           "property_values":[
              {
                 "property_id":200,
                 "property_name":"Primary color",
                 "scale_id":null,
                 "scale_name":null,
                 "values":[
                    "Bronze"
                 ],
                 "value_ids":[
                    1216
                 ]
              }
           ],
           "offerings":[
              {
                 "offering_id":4244423138,
                 "price":{
                    "amount":300,
                    "divisor":100,
                    "currency_code":"GBP",
                    "currency_formatted_short":"\\u00a33.00",
                    "currency_formatted_long":"\\u00a33.00 GBP",
                    "currency_formatted_raw":"3.00"
                 },
                 "quantity":56,
                 "is_enabled":1,
                 "is_deleted":0
              }
           ],
           "is_deleted":0
        }
     ],
  "price_on_property": [200],
  "quantity_on_property": [200],
  "sku_on_property": [200]
  </code></pre>
  
  <p>Etsy is using Oauth1, POST and GET requests work fine in Python, but don't work in POSTMAN, returning an invalid signature error.</p>
  
  <p>Maybe they are doing something differently that causes this behaviour?</p>
  
  <p>I need to build a request that simply takes product data, oauth1 details, and sends it to Etsy.
  Please let me know what I'm missing.</p>