a tweak due to PyCharm

csst_common/data_manager.py

@@ -353,8 +353,6 @@ DIR_SIM = {
 
 if __name__ == "__main__":
     # test C3
-    import os
-
     dm = CsstMbiDataManager(
         ver_sim="C3", dir_l0="/data/L1Pipeline/msc/MSC_0000020", dir_l1="/data/L1Pipeline/msc/work")
     print("----- L0 images -----")
@@ -372,8 +370,6 @@ if __name__ == "__main__":
     print(dm.l1_detector(25, "img.fits"))
 
     # test C5.1
-    import os
-
     dm = CsstMbiDataManager(
         ver_sim="C5.1", dir_l0="/data/sim_data/MSC_0000100", dir_l1="/home/user/L1Pipeline/msc/work")
     print("----- available detectors -----")