python wrapper: convert input source to line generator

inputwrapper.py

"""
Convert an input source (file, string, or file descriptor)
into a generator that provides a line at a time.

Online challenges provide input on stdin, but for testing,
it can be useful to provide input via a file or a string.
This wrapper takes any of these formats and returns an
iterator that will provide the input a line at a time.
"""
def input_from_string(data):
    """ Input generator, using given data as input """
    for line in data.splitlines():
        yield line

def input_from_file(file):
    """ Input generator, using given file as input """
    return input_from_fd(open(file, "r"))

def input_from_fd(fd):
    """ Input generator, using given file descriptor as input """
    for line in fd:
        yield line.rstrip()