modified wait till done method to include check frequency as a argument (#1340)

Author: Gabefire

labelbox/schema/task.py

@@ -58,14 +58,19 @@ def refresh(self) -> None:
         for field in self.fields():
             setattr(self, field.name, getattr(tasks[0], field.name))
 
-    def wait_till_done(self, timeout_seconds: int = 300) -> None:
+    def wait_till_done(self,
+                       timeout_seconds: float = 300.0,
+                       check_frequency: float = 2.0) -> None:
         """ Waits until the task is completed. Periodically queries the server
-        to update the task attributes.
+            to update the task attributes.
 
-        Args:
-            timeout_seconds (float): Maximum time this method can block, in seconds. Defaults to five minutes.
-        """
-        check_frequency = 2  # frequency of checking, in seconds
+            Args:
+                timeout_seconds (float): Maximum time this method can block, in seconds. Defaults to five minutes.
+                check_frequency (float): Frequency of queries to server to update the task attributes, in seconds. Defaults to two seconds. Minimal value is two seconds. 
+            """
+        if check_frequency < 2.0:
+            raise ValueError(
+                "Expected check frequency to be two seconds or more")
         while timeout_seconds > 0:
             if self.status != "IN_PROGRESS":
                 # self.errors fetches the error content.