Move some harmless imports to file scope. NFC.

copycat/workspace.py

@@ -1,6 +1,9 @@
 import logging
 
 import formulas
+from bond import Bond
+from correspondence import Correspondence
+from letter import Letter
 from workspaceString import WorkspaceString
 
 
@@ -119,8 +122,6 @@ class Workspace(object):
 
     def numberOfUnreplacedObjects(self):
         """A list of all unreplaced objects in the inital string"""
-        from letter import Letter
-
         objects = [o for o in self.objects
                    if o.string == self.initial and isinstance(o, Letter)]
         objects = [o for o in objects if not o.replacement]
@@ -135,13 +136,9 @@ class Workspace(object):
 
     def numberOfBonds(self):
         """The number of bonds in the workspace"""
-        from bond import Bond
-
         return len([o for o in self.structures if isinstance(o, Bond)])
 
     def correspondences(self):
-        from correspondence import Correspondence
-
         return [s for s in self.structures if isinstance(s, Correspondence)]
 
     def slippages(self):