python function to read all descendant lines of a given line which are not empty

Question

the function will take two parameters (line, txtfile) and should return all the descendant lines after the line parameter from txtfile which are not empty

for example the text file contains:

line1
line2

line3
line4
line5

the function should return line1line2 if line1 is given as parameter or line3line4line5 if line3 is given as parameter

Answer 1

def fun(line, filename):
  file = open(filename, 'r') 
  output=''
  empty=False
  for i in file:
    if(i.rstrip('\n')==line or empty):
      empty=True
      output+=i.rstrip('\n')
      if(i.rstrip('\n')==''):
        empty=False
  return output
filename=input("Enter file name")
line=input("Input line")
output=fun(line,filename)
print(output)