Not able to call post function on any of the object (Product, Collect, Metafield)

[ankesh4040]

Getting error : CurlException: Request failed with HTTP Code 400.

$metafieldv = [
'namespace' => "custom", 'key' => "ship_time", 'value' => "API updated", 'type' => 'single_line_text_field' ] ; $metafields = $shopify->Product('7543539269680')->Metafield->post($metafieldv);

/// Getting error...............

$collectData = [ 'product_id' => '7543539269680', 'collection_id' =>'281608945712', ];

$collect = $shopify->Collect->post($collectData );

/// Getting error...............