def determine_edit_type(values, previous_values):
	""" Determine whether an edit is editorial (0) or content (1). 
	This is dependent on whether there are substantial additions in content volume. 
	
	It is only a content contribution if:
		1) both text and links/urls are added (not text in isolation)
		2) images are added. 
	Editorial counts:
		- words only
		- categories
		- any deletions
	"""

	changes = {key: values[key] - previous_values.get(key, 0) for key in values}

	if changes["images"] > 0:
		return "content"

	elif changes["words"] > 0 and changes["links"]+changes["urls"] > 0:
		return "content"
	
	else:
		return "editorial"