1 files changed, 30 insertions, 0 deletions
diff --git a/challenge-282/steven-wilson/python/ch-2.py b/challenge-282/steven-wilson/python/ch-2.py
new file mode 100644
index 0000000000..199cffc157
--- /dev/null
+++ b/challenge-282/steven-wilson/python/ch-2.py
@@ -0,0 +1,30 @@
+#!/usr/bin/env python3
+
+from itertools import groupby
+
+
+def changing_keys(string):
+    """ Given an alphabetic string as typed by user,return the number of times
+    user had to change the key to type the given string. Changing key is
+    defined as using a key different from the last used key. The shift and caps
+    lock keys won’t be counted.
+    >>> changing_keys('pPeERrLl')
+    3
+    >>> changing_keys('rRr')
+    0
+    >>> changing_keys('GoO')
+    1
+    """
+    if len(string) == 0:
+        return 0
+
+    if not all(c.isalpha() for c in string):
+        raise ValueError('User should type an aphabetic string')
+
+    return len([item for _, item in groupby(string.casefold())]) - 1
+
+
+if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod(verbose=True)