How do I search a csv file and get the indentation right so this works

import csv #assuming the file is in csv format, import csv

#Task: Search for a teacher, and return the subject they teach
"""File contents
Mr A : Maths
Mr B: History
Mr C: Computing
"""

def main():
      #open the file
      with open("teacherbook1.csv", "r") as teacherfile:
            teacher=input("Enter teacher you are looking for:")
            teacherfileReader=csv.reader(teacherfile)
            for row in teacherfileReader:
                  for field in row:
                        if field==teacher:
                              print(row[1])
                              break
                        else:
                              main()



main()

Enter teacher you are looking for:Mr A
Philosophy
Enter teacher you are looking for:Mr B
Enter teacher you are looking for:Mr C
Enter teacher you are looking for:Mr X
Enter teacher you are looking for: