diff --git a/src/diffuse/vcs/bzr.py b/src/diffuse/vcs/bzr.py
index 3277f01..e7b4669 100644
--- a/src/diffuse/vcs/bzr.py
+++ b/src/diffuse/vcs/bzr.py
@@ -20,13 +20,14 @@
 import os
 
 from diffuse import utils
+from diffuse.preferences import Preferences
 from diffuse.vcs.folder_set import FolderSet
 from diffuse.vcs.vcs_interface import VcsInterface
 
 
 # Bazaar support
 class Bzr(VcsInterface):
-    def getFileTemplate(self, prefs, name):
+    def getFileTemplate(self, prefs: Preferences, name: str) -> VcsInterface.PathRevisionList:
         # merge conflict
         left = name + '.OTHER'
         right = name + '.THIS'
diff --git a/src/diffuse/vcs/cvs.py b/src/diffuse/vcs/cvs.py
index 306f2e2..fc90088 100644
--- a/src/diffuse/vcs/cvs.py
+++ b/src/diffuse/vcs/cvs.py
@@ -22,13 +22,14 @@ import os
 from gettext import gettext as _
 
 from diffuse import utils
+from diffuse.preferences import Preferences
 from diffuse.vcs.folder_set import FolderSet
 from diffuse.vcs.vcs_interface import VcsInterface
 
 
 # CVS support
 class Cvs(VcsInterface):
-    def getFileTemplate(self, prefs, name):
+    def getFileTemplate(self, prefs: Preferences, name: str) -> VcsInterface.PathRevisionList:
         return [(name, 'BASE'), (name, None)]
 
     def getCommitTemplate(self, prefs, rev, names):
diff --git a/src/diffuse/vcs/darcs.py b/src/diffuse/vcs/darcs.py
index 28331f3..0607f8f 100644
--- a/src/diffuse/vcs/darcs.py
+++ b/src/diffuse/vcs/darcs.py
@@ -20,13 +20,14 @@
 import os
 
 from diffuse import utils
+from diffuse.preferences import Preferences
 from diffuse.vcs.folder_set import FolderSet
 from diffuse.vcs.vcs_interface import VcsInterface
 
 
 # Darcs support
 class Darcs(VcsInterface):
-    def getFileTemplate(self, prefs, name):
+    def getFileTemplate(self, prefs: Preferences, name: str) -> VcsInterface.PathRevisionList:
         return [(name, ''), (name, None)]
 
     def _getCommitTemplate(self, prefs, names, rev):
diff --git a/src/diffuse/vcs/git.py b/src/diffuse/vcs/git.py
index 20b2d5f..e741315 100644
--- a/src/diffuse/vcs/git.py
+++ b/src/diffuse/vcs/git.py
@@ -27,7 +27,7 @@ from diffuse.vcs.vcs_interface import VcsInterface
 
 # Git support
 class Git(VcsInterface):
-    def getFileTemplate(self, prefs, name):
+    def getFileTemplate(self, prefs: Preferences, name: str) -> VcsInterface.PathRevisionList:
         return [(name, 'HEAD'), (name, None)]
 
     def getCommitTemplate(self, prefs, rev, names):
diff --git a/src/diffuse/vcs/hg.py b/src/diffuse/vcs/hg.py
index 6dc540e..88deb47 100644
--- a/src/diffuse/vcs/hg.py
+++ b/src/diffuse/vcs/hg.py
@@ -22,6 +22,7 @@ import os
 from typing import Optional
 
 from diffuse import utils
+from diffuse.preferences import Preferences
 from diffuse.vcs.folder_set import FolderSet
 from diffuse.vcs.vcs_interface import VcsInterface
 
@@ -51,7 +52,7 @@ class Hg(VcsInterface):
             return self.working_rev
         return f'p1({rev})'
 
-    def getFileTemplate(self, prefs, name):
+    def getFileTemplate(self, prefs: Preferences, name: str) -> VcsInterface.PathRevisionList:
         return [(name, self._getPreviousRevision(prefs, None)), (name, None)]
 
     def _getCommitTemplate(self, prefs, names, cmd, rev):
diff --git a/src/diffuse/vcs/mtn.py b/src/diffuse/vcs/mtn.py
index 7330e32..749754a 100644
--- a/src/diffuse/vcs/mtn.py
+++ b/src/diffuse/vcs/mtn.py
@@ -21,27 +21,28 @@ import os
 import shlex
 
 from diffuse import utils
+from diffuse.preferences import Preferences
 from diffuse.vcs.folder_set import FolderSet
 from diffuse.vcs.vcs_interface import VcsInterface
 
 
 # Monotone support
 class Mtn(VcsInterface):
-    def getFileTemplate(self, prefs, name):
+    def getFileTemplate(self, prefs: Preferences, name: str) -> VcsInterface.PathRevisionList:
         # FIXME: merge conflicts?
         return [(name, 'h:'), (name, None)]
 
     def getCommitTemplate(self, prefs, rev, names):
         # build command
         vcs_bin = prefs.getString('mtn_bin')
-        ss = utils.popenReadLines(
+        lines = utils.popenReadLines(
             self.root,
             [vcs_bin, 'automate', 'select', '-q', rev],
             prefs,
             'mtn_bash')
-        if len(ss) != 1:
+        if len(lines) != 1:
             raise IOError('Ambiguous revision specifier')
-        args = [vcs_bin, 'automate', 'get_revision', ss[0]]
+        args = [vcs_bin, 'automate', 'get_revision', lines[0]]
         # build list of interesting files
         fs = FolderSet(names)
         pwd, isabs = os.path.abspath(os.curdir), False
@@ -50,15 +51,15 @@ class Mtn(VcsInterface):
         # run command
         prev = None
         removed, added, modified, renamed = {}, {}, {}, {}
-        ss = utils.popenReadLines(self.root, args, prefs, 'mtn_bash')
+        lines = utils.popenReadLines(self.root, args, prefs, 'mtn_bash')
         i = 0
-        while i < len(ss):
+        while i < len(lines):
             # process results
-            s = shlex.split(ss[i])
+            line_args = shlex.split(lines[i])
             i += 1
-            if len(s) < 2:
+            if len(line_args) < 2:
                 continue
-            arg, arg1 = s[0], s[1]
+            arg, arg1 = line_args[0], line_args[1]
             if arg == 'old_revision' and len(arg1) > 2:
                 if prev is not None:
                     break
@@ -82,26 +83,27 @@ class Mtn(VcsInterface):
                 if fs.contains(k):
                     modified[arg1] = k
             elif arg == 'rename':
-                s = shlex.split(ss[i])
+                line_args = shlex.split(lines[i])
                 i += 1
-                if len(s) > 1 and s[0] == 'to':
+                if len(line_args) > 1 and line_args[0] == 'to':
                     # renamed file
                     k0 = os.path.join(self.root, prefs.convertToNativePath(arg1))
-                    k1 = os.path.join(self.root, prefs.convertToNativePath(s[1]))
+                    k1 = os.path.join(self.root, prefs.convertToNativePath(line_args[1]))
                     if fs.contains(k0) or fs.contains(k1):
-                        renamed[s[1]] = (arg1, k0, k1)
+                        renamed[line_args[1]] = (arg1, k0, k1)
         if removed or renamed:
             # remove directories
             removed_dirs = set()
-            for s in utils.popenReadLines(
+            lines = utils.popenReadLines(
                 self.root,
                 [vcs_bin, 'automate', 'get_manifest_of', prev],
                 prefs,
                 'mtn_bash'
-            ):
-                s = shlex.split(s)
-                if len(s) > 1 and s[0] == 'dir':
-                    removed_dirs.add(s[1])
+            )
+            for line in lines:
+                line_args = shlex.split(line)
+                if len(line_args) > 1 and line_args[0] == 'dir':
+                    removed_dirs.add(line_args[1])
             for k in removed_dirs:
                 for m in removed, modified:
                     if k in m:
diff --git a/src/diffuse/vcs/rcs.py b/src/diffuse/vcs/rcs.py
index 41fa203..f6d721a 100644
--- a/src/diffuse/vcs/rcs.py
+++ b/src/diffuse/vcs/rcs.py
@@ -22,12 +22,13 @@ import os
 from gettext import gettext as _
 
 from diffuse import utils
+from diffuse.preferences import Preferences
 from diffuse.vcs.vcs_interface import VcsInterface
 
 
 # RCS support
 class Rcs(VcsInterface):
-    def getFileTemplate(self, prefs, name):
+    def getFileTemplate(self, prefs: Preferences, name: str) -> VcsInterface.PathRevisionList:
         args = [
             prefs.getString('rcs_bin_rlog'),
             '-L',
diff --git a/src/diffuse/vcs/svk.py b/src/diffuse/vcs/svk.py
index bd8dfe5..5e25e4b 100644
--- a/src/diffuse/vcs/svk.py
+++ b/src/diffuse/vcs/svk.py
@@ -19,7 +19,7 @@
 
 import os
 
-from typing import Tuple
+from typing import Optional, Tuple
 
 from diffuse import utils
 from diffuse.vcs.svn import Svn
@@ -41,7 +41,7 @@ class Svk(Svn):
         return s[0], s[4:]
 
     @staticmethod
-    def _getPreviousRevision(rev: str) -> str:
+    def _getPreviousRevision(rev: Optional[str]) -> str:
         if rev is None:
             return 'HEAD'
         if rev.endswith('@'):
diff --git a/src/diffuse/vcs/svn.py b/src/diffuse/vcs/svn.py
index fc14a56..0e4327d 100644
--- a/src/diffuse/vcs/svn.py
+++ b/src/diffuse/vcs/svn.py
@@ -24,6 +24,7 @@ from gettext import gettext as _
 from typing import Optional, Tuple
 
 from diffuse import utils
+from diffuse.preferences import Preferences
 from diffuse.vcs.folder_set import FolderSet
 from diffuse.vcs.vcs_interface import VcsInterface
 
@@ -54,7 +55,7 @@ class Svn(VcsInterface):
         return s[0], s[k:]
 
     @staticmethod
-    def _getPreviousRevision(rev: str) -> str:
+    def _getPreviousRevision(rev: Optional[str]) -> str:
         if rev is None:
             return 'BASE'
         m = int(rev)
@@ -71,7 +72,7 @@ class Svn(VcsInterface):
                     break
         return self.url
 
-    def getFileTemplate(self, prefs, name):
+    def getFileTemplate(self, prefs: Preferences, name: str) -> VcsInterface.PathRevisionList:
         # FIXME: verify this
         # merge conflict
         escaped_name = utils.globEscape(name)
diff --git a/src/diffuse/vcs/vcs_interface.py b/src/diffuse/vcs/vcs_interface.py
index 63800e8..0cef9d3 100644
--- a/src/diffuse/vcs/vcs_interface.py
+++ b/src/diffuse/vcs/vcs_interface.py
@@ -17,14 +17,22 @@
 # with this program; if not, write to the Free Software Foundation, Inc.,
 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
+from typing import List, Optional, Tuple
+
+from diffuse.preferences import Preferences
+
+
 class VcsInterface:
     """Interface for the VCSs."""
 
+    PathRevisionPair = Tuple[Optional[str], Optional[str]]
+    PathRevisionList = List[PathRevisionPair]
+
     def __init__(self, root: str):
         """The object will initialized with the repository's root folder."""
         self.root = root
 
-    def getFileTemplate(self, prefs, name):
+    def getFileTemplate(self, prefs: Preferences, name: str) -> PathRevisionList:
         """Indicates which revisions to display for a file when none were explicitly
            requested."""