fix dir creating bug

Author: Xiao Wang

main.py

@@ -72,14 +72,17 @@ def construct_single_chain_candidate(params,save_path):
     #first build a dict from the input text configure file
     single_chain_pdb_input = os.path.abspath(params['P'])
     single_chain_pdb_dir = os.path.join(save_path,"single_chain_pdb")
-    os.makedirs(single_chain_pdb_dir,exist_ok=True)
+    
     #if os.path.exists(single_chain_pdb_dir):
         #shutil.rmtree(single_chain_pdb_dir)
     #delete_dir(single_chain_pdb_dir)
     if not os.path.isdir(single_chain_pdb_input):
+        os.makedirs(single_chain_pdb_dir,exist_ok=True)
         from ops.os_operation import extract_compressed_file
         single_chain_pdb_dir=extract_compressed_file(single_chain_pdb_input,single_chain_pdb_dir)
     else:
+        if os.path.exists(single_chain_pdb_dir):
+            shutil.rmtree(single_chain_pdb_dir)
         from ops.os_operation import copy_directory
         single_chain_pdb_dir = copy_directory(single_chain_pdb_input,single_chain_pdb_dir)
     from ops.io_utils import read_structure_txt