def _stable_names(self):
stable_names=[]<EOL>for i in range(len(self.stable_el)):<EOL><INDENT>stable_names.append(self.stable_el[i][<NUM_LIT:0>])<EOL><DEDENT>self.stable_names=stable_names<EOL>
This private method extracts the element names from stable_el.
Note that stable_names is a misnomer as stable_el also contains
unstable element names with a number 999 for the *stable* mass
numbers. (?!??)