+ """
+ Builds a list of SDN environment files to be used in the deploy cmd.
+
+ This function recursively searches an sdn_map. First the sdn controller is
+ matched and then the function looks for enabled features for that
+ controller to determine which environment files should be used. By
+ default the feature will be checked if set to true in deploy settings to be
+ added to the list. If a feature does not have a boolean value, then the
+ key and value pair to compare with are checked as a tuple (k,v).
+
+ :param ds: deploy settings
+ :param sdn_map: SDN map to recursively search
+ :param env_list: recursive var to hold previously found env_list
+ :return: A list of env files
+ """