Merge pull request sonic-net#132 from vdahiya12/adding_changes_for_ba…

…se_api

[sonic_platform_base][fan_drawer_base] adding get_fan definition to the base api definitions of fan_drawer base class

sonic_platform_base/fan_drawer_base.py

@@ -37,6 +37,29 @@ def get_all_fans(self):
         """
         return self._fan_list
 
+     def get_fan(self, index):
+        """
+        Retrieves fan module represented by (0-based) index <index>
+
+        Args:
+            index: An integer, the index (0-based) of the fan module to
+            retrieve
+
+        Returns:
+            An object dervied from FanBase representing the specified fan
+            module
+        """
+        fan = None
+
+        try:
+            fan = self._fan_list[index]
+        except IndexError:
+            sys.stderr.write("Fan index {} out of range (0-{})\n".format(
+                             index, len(self._fan_list)-1))
+
+        return fan
+
+
     def set_status_led(self, color):
         """
         Sets the state of the fan drawer status LED