# search file for string
def searchLineWithString(self, string, file):
    for num, line in enumerate(file, 1):
        if string in line:
            return num - 1
 
# edit line dependend on provided parameter
def editLine(self, file, searchString, newLine):
    selectedFile = open(file, "r")
    readSelectedFile = selectedFile.readlines()
    selectedFile.close()
    # find specific line
    lineToEdit = searchLineWithString(self, searchString, readSelectedFile)
    # edit required line
    readSelectedFile[lineToEdit] = newLine   
 
    # write lines to files
    selectedFile = open(file, "w")
    selectedFile.writelines(readSelectedFile)
    selectedFile.close()