DeprecationUtilities.py: Add a utility function

Add a check_deprecation utility function to log a
warning message in case deprecated parameters are
used.

coalib/misc/DeprecationUtilities.py

@@ -0,0 +1,28 @@
+import logging
+
+
+def check_deprecation(param_list):
+    """
+    Shows a deprecation warning message if the parameters
+    passed are not ``None``.
+
+    :param param_list:
+        A dictionary of parameters with their names mapped
+        to their values being checked for deprecation.
+
+    >>> from testfixtures import LogCapture
+    >>> from collections import OrderedDict
+    >>> param_list = OrderedDict([('foo', None),
+    ...                           ('bar', 'Random'),
+    ...                           ('baz', 1773)])
+    >>> with LogCapture() as capture:
+    ...     check_deprecation(param_list)
+    ...     print(capture)
+    root WARNING
+      bar parameter is deprecated
+    root WARNING
+      baz parameter is deprecated
+    """
+    for param_name, param_value in param_list.items():
+        if param_value is not None:
+            logging.warning('{} parameter is deprecated'.format(param_name))