Avoid using ambiguous variable name "l"

Fixes the issue E741 reported by flake8 >= 3.8.
https://www.flake8rules.com/rules/E741.html

picard/ui/cdlookup.py

@@ -73,8 +73,8 @@ class CDLookupDialog(PicardDialog):
                                       _("Labels"), _("Catalog #s"), _("Barcode")])
         self.ui.submit_button.setIcon(QtGui.QIcon(":/images/cdrom.png"))
         if self.releases:
-            def myjoin(l):
-                return "\n".join(l)
+            def myjoin(values):
+                return "\n".join(values)
 
             self.ui.results_view.setCurrentIndex(0)
             selected = None

picard/ui/options/interface.py

@@ -153,7 +153,7 @@ class InterfaceOptionsPage(OptionsPage):
         self.ui = Ui_InterfaceOptionsPage()
         self.ui.setupUi(self)
         self.ui.ui_language.addItem(_('System default'), '')
-        language_list = [(l[0], l[1], _(l[2])) for l in UI_LANGUAGES]
+        language_list = [(lang[0], lang[1], _(lang[2])) for lang in UI_LANGUAGES]
 
         def fcmp(x):
             return locale.strxfrm(x[2])

picard/util/filenaming.py

@@ -155,8 +155,8 @@ def shorten_path(path, length, mode):
     length: Maximum number of code points / bytes allowed in a node.
     mode: One of SHORTEN_BYTES, SHORTEN_UTF16, SHORTEN_UTF16_NFD.
     """
-    def shorten(n, l):
-        return n and shorten_filename(n, l, mode).strip() or ""
+    def shorten(name, length):
+        return name and shorten_filename(name, length, mode).strip() or ""
     dirpath, filename = os.path.split(path)
     fileroot, ext = os.path.splitext(filename)
     return os.path.join(
@@ -203,8 +203,8 @@ def _make_win_short_filename(relpath, reserved=0):
     remaining = MAX_DIRPATH_LEN - reserved
 
     # to make things more readable...
-    def shorten(p, l):
-        return shorten_path(p, l, mode=SHORTEN_UTF16)
+    def shorten(path, length):
+        return shorten_path(path, length, mode=SHORTEN_UTF16)
     xlength = _get_utf16_length
 
     # shorten to MAX_NODE_LEN from the beginning

test/test_bytes2human.py

@@ -106,13 +106,13 @@ class Testbytes2human(PicardTestCase):
     @staticmethod
     def _save_expected_to(path, a_list):
         with open(path, 'wb') as f:
-            f.writelines([l + "\n" for l in a_list])
+            f.writelines([line + "\n" for line in a_list])
             f.close()
 
     @staticmethod
     def _read_expected_from(path):
         with open(path, 'r') as f:
-            lines = [l.rstrip("\n") for l in f.readlines()]
+            lines = [line.rstrip("\n") for line in f.readlines()]
             f.close()
             return lines