def to_pn(self, sub_letter=None):
string = str(self)<EOL>if '<STR_LIT:.>' not in string:<EOL><INDENT>return string<EOL><DEDENT>if not string[-<NUM_LIT:1>].isalpha():<EOL><INDENT>if sub_letter is not None:<EOL><INDENT>return string.replace('<STR_LIT:.>', sub_letter)<EOL><DEDENT>return string<EOL><DEDENT>letter = string[-<NUM_LIT:1>]<EOL>return string.replace('<STR_LIT:.>', letter)[:-<NUM_LIT:1>]<EOL>
Returns the part number equivalent.  For instance,
a '1k' would still be '1k', but a
'1.2k' would, instead, be a '1k2'
:return: