Update count_entity_total method following the review

Author: jadsonmonteiro

README.md

@@ -271,11 +271,31 @@ Count the number of inserted entities. This method corresponds to a [POST reques
 from pyslicer import SlicingDice
 client = SlicingDice('MASTER_OR_READ_API_KEY', uses_test_endpoint=False)
 
-tables = {
-    'tables': [
-        'default'
-    ]
+print client.count_entity_total()
+```
+
+#### Output example
+
+```json
+{
+    "status": "success",
+    "result": {
+        "total": 42
+    },
+    "took": 0.103
 }
+```
+
+### `count_entity_total(tables)`
+Count the total number of inserted entities in the given tables. This method corresponds to a [POST request at /query/count/entity/total](http://panel.slicingdice.com/docs/#api-details-api-endpoints-get-query-count-entity-total).
+
+#### Request example
+
+```python
+from pyslicer import SlicingDice
+client = SlicingDice('MASTER_OR_READ_API_KEY', uses_test_endpoint=False)
+
+tables = ['default']
 
 print client.count_entity_total(tables)
 ```

pyslicer/client.py

@@ -213,21 +213,22 @@ def count_entity(self, query):
         url = base_url + URLResources.QUERY_COUNT_ENTITY
         return self._count_query_wrapper(url, query)
 
-    def count_entity_total(self, tables=None):
+    def count_entity_total(self, tables=[]):
         """Make a count entity total query
 
         Keyword arguments:
         tables -- A dictionary containing the tables in which
                   the total query will be performed
         """
-        if tables is None:
-            tables = {}
+        query = {
+            'tables': tables
+        }
         base_url = self._wrapper_test()
         url = base_url + URLResources.QUERY_COUNT_ENTITY_TOTAL
         return self._make_request(
             url=url,
             req_type="post",
-            json_data=ujson.dumps(tables),
+            json_data=ujson.dumps(query),
             key_level=0)
 
     def count_event(self, query):