refactor dir list reading

uninstallfillpdf.py

@@ -14,27 +14,21 @@ def readInstallDirectoriesFromConfig():
     """Read the config file and find install dirs.
 
     Returns:
-        a list consisting of the install directories specified in
+        a set consisting of the install directories specified in
         the config file. An empty list in case of non-existing config
         file.
 
     """
-    installdirs = []
     try:
         with open(CONFIGFILE, "r") as configfile:
-            for line in [l.strip("\n") for l in configfile.readlines() if
-                         l.startswith(CONFIG_INSTALLDIR + CONFIG_SEPARATOR)]:
-                try:
-                    installdirs.append(line.split(CONFIG_SEPARATOR,
-                                                  maxsplit=1  # max 2 parts
-                                                  )[1])
-                except IndexError:
-                    print("Debug: impossible index error " +
-                          "in config file reading.")
-        return installdirs
+            return {
+                line.strip("\n").split(CONFIG_SEPARATOR, maxsplit=1)[1]
+                for line in configfile.readlines()
+                if line.startswith(CONFIG_INSTALLDIR + CONFIG_SEPARATOR)
+            }  # set for removind duplicates
     except FileNotFoundError:
         print("Debug: no config file found.")
-        return []
+        return set()
 
 
 def removeInstallationLinks(where):