@property<EOL><INDENT>def effective_len(self):<DEDENT>
if self._effective_len is None:<EOL><INDENT>self._effective_len = len([nuc for nuc in self.sequenceData<EOL>if nuc != "<STR_LIT:N>" and nuc != "<STR_LIT:n>"])<EOL><DEDENT>return self._effective_len<EOL>
Get the length of the sequence if N's are disregarded.