pythonは、リストに最も多く表示されている要素を返します.

#                 



def showmax(lt):

    index1 = 0                       #             

    max = 0                          #           

    for i in range(len(lt)):

        flag = 0                    #            

        for j in range(i+1,len(lt)): #  i       

            if lt[j] == lt[i]:

                flag += 1           #            ，flag+1

        if flag > max:              #                ，         
            max = flag
            index1 = i

    return lt[index1]               #         

lt = [1,1,2,3,3,5,6,8,9,4,6,18,6,44,6,44,44,44]

print(showmax(lt))