def getline_input():
    """
    Method collects user inputs for phone line number 
    INPUTS: none 
    OUTPUT: Returns int
    """
    loop = True
    while loop:
        line = input('Enter line no. (default=1): ')
        if line == '':
            return 1
        if line.isdigit():
            if int(line) <= 0:
                print(f"Invalid input '{line}' >> Expecting integer(>=1).")
            else:
                loop = False
        else:
            print(f"Invalid input '{line}' >> Expecting integer(>=1).")
    return int(line)
