def p_modules(self, p):
        """modules : modules module
                   | module"""
        n = len(p)
        if n == 3:
            p[0] = p[1] + [p[2]]
        elif n == 2:
            p[0] = [p[1]]
def p_modules(self, p):
        """modules : modules module
                   | module"""
        n = len(p)
        if n == 3:
            p[0] = p[1] + [p[2]]
        elif n == 2:
            p[0] = [p[1]]
def p_modules ( self , p ) : n = len ( p ) if n == 3 : p [ 0 ] = p [ 1 ] + [ p [ 2 ] ] elif n == 2 : p [ 0 ] = [ p [ 1 ] ]
modules : modules module
                   | module
modules : modules module | module