python implementation of the book lending system

from flask import Flask,render_template
from flask import request
from DB import createdb
from flask import session

app = Flask(__name__)
['SECRET_KEY'] = '123456'

# Home-->Login Page
@('/')
def hello_world():
  return render_template('')

# Registration page
@('/showregister')
def showregister():
  return render_template('')

# Login page submission information
@('/login',methods=['GET','POST'])
def login():
  username = ('username')
  stuid = ('password') # The student number is the password
  flag = (stuid,username)
  if flag:
    session['username'] = username
    session['stuid'] = stuid
    return render_template('', stuid=stuid, username=username)
  else:
    return render_template('')

# Submitting information on the registration page
@('/register',methods=['GET','POST'])
def register():
  username = ('username')
  stuid = ('password')# The student number is the password
  return (stuid,username)

# Display book information page
@('/ShowBook')
def ShowBook():
  return ()

# Show Add Books page
@('/AddBook')
def AddBook():
  return render_template('')

# Add book information
@('/Add',methods=['GET','POST'])
def Add():
  bookName = ('bookname')
  bookAuthor = ('author')
  return (bookName,bookAuthor)

# Display information on borrowed books
@('/BorrowBook')
def BorrowBook():
  return ()

# Display information on borrowed books
@('/Borrow',methods=['GET','POSt'])
def Borrow():
  bookName = ('bookName')
  bookAuthor = ('bookAuthor')
  username = ('username')
  stuid = ('stuid')
  return (username,stuid,bookName,bookAuthor)

# Display information on borrowed books
@('/ReturnBook',methods=['GET','POST'])
def ReturnBook():
  bookName = ("bookName")
  return (bookName)

# Display information on borrowed books
@('/UserInfo')
def UserInfo():
  stuid = ('stuid')
  username = ('username')
  return render_template('',stuid = stuid,username = username)


if __name__ == '__main__':
  (debug=True)