Add extra data option to add_source

src/pycrunch/importing.py

@@ -5,7 +5,7 @@
 
 import six
 
-from pycrunch import shoji, csvlib
+from pycrunch import csvlib, shoji
 
 
 class Importer(object):
@@ -53,13 +53,13 @@ def wait_for_batch_status(self, batch, status):
             raise ValueError("The batch did not reach the '%s' state in the "
                              "given time. Please check again later." % status)
 
-    def add_source(self, ds, filename, fp, mimetype):
+    def add_source(self, ds, filename, fp, mimetype, data={}):
         """Create a new Source on the given dataset and return its URL."""
         sources_url = ds.user_url.catalogs['sources']
         # Don't call Catalog.post here (which would force application/json);
         # we want requests.Session to set multipart/form-data with a boundary.
         new_source_url = ds.session.post(
-            sources_url, files={"uploaded_file": (filename, fp, mimetype)}
+            sources_url, files={"uploaded_file": (filename, fp, mimetype)}, data=data
         ).headers["Location"]
 
         if self.strict is not None: