subsection : HEADERSUBSEC texts
                      | HEADERSUBSEC texts labeldecls opttexts

def p_subsection(self, subsection):
        '''subsection : HEADERSUBSEC texts
                      | HEADERSUBSEC texts labeldecls opttexts'''
        content = subsection[3] if len(subsection) > 3 else []
        subsection[0] = Subsection(subsection[1], subsection[2], content)