replacement

def list_replacement(lst,k,new_list): 
    answer=[]
    new=[]
    for i in range (len(lst)):
        if lst[i]>k:
            lst[i]=new_list
            new+=lst[i]
        return new
    temp=[]
    for j in new:
        for z in j:
            temp.append(z)
        return temp
    return answer
print(list_replacement([6,65,10,4,20],15,[1,2,3]))