in mpl_client.py: in read_data(): add a test to check that the io_function is a String and not a function object.
                                  The problem with function objects is that it may be a security issue. The server
	                          has a limited allowed functions (known_functions).
                                  If io_function is not a string, a WARNING is thrown and io_function
				  is replaced with io_function.__name__.