def is_stable(self,species):
element_name_of_iso            = species.split('<STR_LIT:->')[<NUM_LIT:0>]<EOL>try:<EOL><INDENT>a_of_iso               = int(species.split('<STR_LIT:->')[<NUM_LIT:1>])<EOL><DEDENT>except ValueError: <EOL><INDENT>a_of_iso               = <NUM_LIT><EOL><DEDENT>idp_of_element_in_stable_names = self.stable_names.index(element_name_of_iso)<EOL>if a_of_iso in self.stable_el[idp_of_element_in_stable_names][<NUM_LIT:1>:]:<EOL><INDENT>return True<EOL><DEDENT>else:<EOL><INDENT>return False<EOL><DEDENT>
This routine accepts input formatted like 'He-3' and checks with
stable_el list if occurs in there.  If it does, the routine
returns True, otherwise False.

Notes
-----
this method is designed to work with an se instance from
nugridse.py. In order to make it work with ppn.py some
additional work is required.

FH, April 20, 2013.