smarter deprecation warning using regex

my/reddit/__init__.py

@@ -15,9 +15,26 @@ REQUIRES = [
     'git+https://github.com/karlicoss/rexport',
 ]
 
-from my.core import warnings as W
+import re
+import traceback
+
+# some hacky traceback to inspect the current stack
+# to see if the user is using the old style of importing
+warn = False
+for f in traceback.extract_stack():
+    line = f.line or '' # just in case it's None, who knows..
+
+    # cover the most common ways of previously interacting with the module
+    if 'import my.reddit ' in (line + ' '):
+        warn = True
+    elif 'from my import reddit' in line:
+        warn = True
+    elif re.match(r"from my\.reddit\simport\s(comments|saved|submissions|upvoted)", line):
+        warn = True
 
 # TODO: add link to instructions to migrate
+if warn:
+    from my.core import warnings as W
     W.high("DEPRECATED! Instead of my.reddit, import from my.reddit.all instead.")