Simplify `command.easy_install.expand_paths`

setuptools/command/easy_install.py

@@ -1459,12 +1459,17 @@ def expand_paths(inputs):
 
             # Yield existing non-dupe, non-import directory lines from it
             for line in lines:
-                if not line.startswith("import"):
+                if line.startswith("import"):
+                    continue
+
                 line = normalize_path(line.rstrip())
-                    if line not in seen:
+                if line in seen:
+                    continue
+
                 seen[line] = 1
                 if not os.path.isdir(line):
                     continue
+
                 yield line, os.listdir(line)