Add documentation about the multifile input

opentech/apply/stream_forms/fields.py

@@ -2,12 +2,17 @@ from django.forms import FileInput, FileField
 
 
 class MultiFileInput(FileInput):
+    """
+    File Input only returns one file from its clean method.
+
+    This passes all files through the clean method and means we have a list of
+    files available for post processing
+    """
     def __init__(self, *args, attrs={}, **kwargs):
         attrs['multiple'] = True
         super().__init__(*args, attrs=attrs, **kwargs)
 
     def value_from_datadict(self, data, files, name):
-        "File widgets take data from FILES, not POST"
         return files.getlist(name)