diff --git a/ur5_control.py b/ur5_control.py
index 189accf..7f43da2 100755
--- a/ur5_control.py
+++ b/ur5_control.py
@@ -683,7 +683,7 @@ def open_gripper():
     fprint("Opening gripper")
     c = ModbusClient(host="192.168.1.21", port=502, auto_open=False, auto_close=False)
     c.open()
-    while not c.is_open():
+    while not c.is_open:
         time.sleep(0.01)
 
     c.write_single_register(112, 0b0)
@@ -700,7 +700,7 @@ def close_gripper():
     fprint("Closing gripper")
     c = ModbusClient(host="192.168.1.21", port=502, auto_open=False, auto_close=False)
     c.open()
-    while not c.is_open():
+    while not c.is_open:
         time.sleep(0.01)
     
     c.write_single_register(435, 0b00000000)