[Python] Is this the correct way to move to the beginning of each line in a text file using...

from sys import argv
script, input_file = argv

hello = open(input_file)

read1 = hello.readline()

print("Line1: ", read1, end = "")
line1 = len(read1) + 1
print(line1)

read2 = hello.readline()

print("Line2: ", read2, end = "")
line2 = len(read1 + read2) + 2
print(line2)

read3 = hello.readline()

print("Line3: ", read3, end = "")
line3 = len(read1 + read2 + read3) + 3
print(line3)

read4 = hello.readline()
print("Line4: ", read4)


beep = input("""I give you the option to choose the line you print:
1. Type: first line
2. Type: second line
3. Type: third line
4. Type: fourth line
""")

if (beep == "first line"):
choice = 0
elif (beep == "second line"):
choice = line1
elif (beep == "third line"):
choice = line2
else:
choice = line3

def runner(f):
hello.seek(f)
green = hello.readline()
print("The line reads: ", green)

runner(choice)


I want to print a particular line from a text file as specified by the user. What I know is that the seek() function takes input in terms of bytes to move the reading pointer at the position corresponding to the size in bytes. Like if a text file has 4 lines and each line is 10 bytes in size (including the newline character) then the size input 11 corresponds to the beginning of the second line. Now if I want to move the reading position to the beginning of the fourth line I will input 31 (sum of sizes of previous lines + 1) to the seek() function to move the reading/writing pointer to the fourth line. But in the attached piece of code I have input sum of the sizes of previous 3 lines + 3 to get the position of the beginning of the fourth line (instead of sum of sizes of previous 3 lines + 1, which makes more sense), but still the code runs perfectly fine. In fact when I replace the +3 (or +2) by +1, I do not get the required line printed.

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