Added validation for item types in all functions in the data client.

Author: kevinlacaille

planet/clients/data.py

@@ -204,7 +204,7 @@ async def create_search(self,
         """
         url = self._searches_url()
 
-        # TODO: validate item_types
+        item_types = [validate_item_type(item) for item in item_types]
         request = {
             'name': name,
             'filter': search_filter,
@@ -237,6 +237,7 @@ async def update_search(self,
         """
         url = f'{self._searches_url()}/{search_id}'
 
+        item_types = [validate_item_type(item) for item in item_types]
         request = {
             'name': name,
             'filter': search_filter,
@@ -395,6 +396,7 @@ async def get_stats(self,
 
         url = f'{self._base_url}{STATS_PATH}'
 
+        item_types = [validate_item_type(item) for item in item_types]
         request = {
             'interval': interval,
             'filter': search_filter,