Diana | Step 1 ::

    import math

    def my_func(stud, grps=2):
    students_list = [[] for x in range(grps)]
    students_amount = math.ceil(len(stud) / grps)
        
    for x, y in zip(range(0,grps), range(0,students_amount * grps,students_amount)):
        students_list[x].extend(stud[y:y + students_amount])
        
        if (students_amount - len(students_list[x])) > 0:
            students_list[x].extend(['__EMPTY__' for x in range(students_amount - len(students_list[x]))])
            
    return (students_list)
    print(my_func(['Anne', 'Diana', 'Gabriele', 'Hannah', 'Inna', 'Luna', 'Maya', 'Nora'], grps=7))

...
import tkinter
from tkinter import StringVar


adfl = ['Alan Alexander Milne', 'Alice Hoffman', 'Alicia Bay Laurel', 'Alison Weir',       'Alistair Cooke','Alycea Ungaro', 'Amanda Quick', 'Ann Durell', 'Anne De Courcy', 'Anne Kent Rush', 'Anne McCaffrey','Anne Purdy', 'Anne Rice', 'Anon', 'Antoine de Saint-Exupery', 'Anya Seton', 'Arthur Conan Doyle','Ashida Kim', 'Aubrey Beardsley', 'BBC', 'Barbara Ann Brennan', 'Barbara Walker', 'Bertrice Small','Betsy Bruce', 'C. S. Lewis', 'Caitlin Matthews', 'Carl Sagan', 'Carol Belanger Grafton', 'Carol Blackman','Carol Kisner', 'Caroline Foley', 'Carolyn Kisner', 'Catherine Coulter', 'Charles Greenstreet Addison','Charlotte Bronte', 'Chic Tabatha Cicero', 'Christina Dodd', 'Christopher Paolini', 'Clare Maxwell-Hudson','Clarissa Pinkola Estés', 'Co Spinhoven', 'D. J. Conway', 'D.H. Lawrence', 'Dan Brown','Daniel M. Mendelowitz', 'Deborah E. Harkness', 'Denise Dumars', 'Denys Hay', 'Diana Gabaldon','Diana L. Paxson', 'Dinah Lovett', 'Dion Fortune', 'Donald M. Anderson']


def update_list(*args):
    frame1_lb.delete(0, 'end')
    search_term = ent_var.get()
    for item in adfl:
        if search_term.lower() in item.lower():
            frame1_lb.insert('end', item)
    return


def author_list():
    # Clear entry box
    ent_var.set("")
    frame1.configure(text='Author')
    frame1_list.set(adfl)
    # Set up trace for list update, only need this one instance to make work
    ent_var.trace("w", update_list)
    frame1_lb.bind('<>', sauthor_list)


def sauthor_list(self):
    caut = frame1_lb.curselection()
    print(caut)
    saut = adfl[caut[0]]
    print(saut)


##########
window = tkinter.Tk()
window.geometry("600x900")
window.resizable(width=False, height=False)
window.wm_title("My Book Library")
window.configure(bg='#5e84d4')
window.update_idletasks()
# Gets the requested values of the height and widht.
windowWidth = window.winfo_width()
windowHeight = window.winfo_height()
# Gets both half the screen width/height and window width/height
positionRight = int((window.winfo_screenwidth() / 2) - windowWidth / 2)
positionDown = int((window.winfo_screenheight() / 2) - windowHeight / 2)
# Positions the window in the center of the page.
window.geometry("+{}+{}".format(positionRight, positionDown))
# Layout of frames

frame1 = tkinter.LabelFrame(window, text='', bg='lightblue')
frame1.place(relx=0.010, rely=0.10, relheight=0.890, relwidth=0.500)
frame1.configure(relief='groove')
frame1.configure(borderwidth="2")
frame1_list = StringVar()
frame1_lb = tkinter.Listbox(frame1, listvariable=frame1_list, width=40, height=44)
frame1_lb.place(x=0.0, y=0.30)
frame1_sb = tkinter.Scrollbar(frame1, orient=tkinter.VERTICAL)
frame1_lb.config(yscrollcommand=frame1_sb.set, bg='white')
frame1_sb.pack(side=tkinter.RIGHT, fill=tkinter.Y)
frame1_sb.config(command=frame1_lb.yview)

frame1a = tkinter.LabelFrame(window, text="Enter letters  - for search")
frame1a.configure(border=2, relief='groove')
frame1a.place(relx=0.010, rely=0.05, relheight=0.05, relwidth=0.500)
ent_var = StringVar()
frame1_ent = tkinter.Entry(frame1a, textvariable=ent_var,  width=40, bg='white')
frame1_ent.place(x=0.0, rely=0.0)
search_term = ent_var.get()


author_list()
window.mainloop()
...