Update app.py

app.py

@@ -28,6 +28,11 @@ import matplotlib.pyplot as plt
 import networkx as nx
 import pandas as pd
 
+if 'MCL_BIN' in os.environ and os.path.isfile(os.environ['MCL_BIN']) and os.access(os.environ['MCL_BIN'], os.X_OK):
+    MCL: Optional[str] = os.environ['MCL_BIN']
+else:
+    MCL = None
+
 
 @dataclass
 class Algorithm:
@@ -70,11 +75,6 @@ class Algorithm:
         return args
 
 
-if 'MCL_BIN' in os.environ and os.path.isfile(os.environ['MCL_BIN']) and os.access(os.environ['MCL_BIN'], os.X_OK):
-    MCL: Optional[str] = os.environ['MCL_BIN']
-else:
-    MCL = None
-
 ALGORITHMS: Dict[str, Algorithm] = {
     'CW_top': Algorithm('cw', 'top'),
     'CW_lin': Algorithm('cw', 'lin'),