How to create a Python class (including class method) to define ttk entry widgets?

Question

I am trying to create a class which will define tkinter entry widgets. I want to be able to pass these parameters to the class:

1. Frame in which to create the entry widget.
2. Text to insert into the entry widget.
3. Width of the entry widget.
4. Column and row to grid the widget in.

My class contains one method which will delete the inserted text and change the fg to black. However, whenever I try to create class instances, I get this error message:

_cnfmerge: fallback due to: 'int' object is not iterable
AttributeError: 'int' object has no attribute 'items'

I don't know if the problem is with my understanding of classes, or of tkinter, or of both. I tried searching for similar problems/situations, but the best I found was an example code (Best way to structure a tkinter application?) which I'm trying to follow. Here's my code:

from tkinter import *
from tkinter import ttk

root = Tk()

class BookData_Entry():
    def __init__(self,root,text,width,column,row,**kwargs):
        self.entry = Entry(root,width,fg='gray')
        self.entry.insert(0,text)
        self.entry.bind('<FocusIn>',self.handle_focus_in)
        self.entry.grid(column=column,row=row)
    def handle_focus_in(self, _):
        self.entry.delete(0,END)
        self.entry.config(fg='black')

BookData_Entry(root,'Please enter the book title',30,1,1)
BookData_Entry(root,"Please enter the author's name",30,2,2)

root.mainloop()

Any help is greatly appreciated.