Add module with utility functions.

For now contains only one function which returns a date string into a
date object.

Utils.py

+"""
+Various utility functions.
+"""
+
+import datetime
+import re
+
+def date_string_to_date(p_date):
+    """
+    Given a date in YYYY-MM-DD, returns a Python date object. Returns None
+    if the date is invalid.
+    """
+    result = None
+
+    parsed_date = re.match(r'(\d{4})-(\d{2})-(\d{2})', p_date)
+
+    if parsed_date:
+        try:
+            date = datetime.date(
+                int(parsed_date.group(1)), # year
+                int(parsed_date.group(2)), # month
+                int(parsed_date.group(3))  # day
+            )
+
+            result = date
+        except ValueError:
+            pass # just return None
+
+    return result