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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def _check_response(response, items, default, indexed, stream, insensitive, fuzzy):
    '''Check the response against the items'''
    # Set selection
    selection = None
    # if indexed, check for index
    if indexed:
        if response.isdigit():
            index_response = int(response)
            if index_response < len(items):
                selection = items[index_response]
    # if not matched by an index, match by text
    if selection is None:
        # insensivitize, if necessary
        original_items = items[:]
        original_response = response
        if insensitive:
            response = response.lower()
            items = [i.lower() for i in items]
        # Check for text matches
        if fuzzy:
            matches = _get_fuzzy_matches(response, items)
        # if insensitive, lowercase the comparison
        else:
            matches = [i for i in items if i.startswith(response)]
        # re-sensivitize if necessary
        if insensitive:
            matches = [
                i for i in original_items
                if i.lower() in matches
            ]
            response = original_response
        num_matches = len(matches)
        # Empty response, no default
        if response == '' and default is None:
            stream.write("[!] an empty response is not valid.\n")
        elif response == '':
            selection = default
        # Bad response
        elif num_matches == 0:
            stream.write("[!] \"{response}\" does not match any of the valid choices.\n".format(
                response=response
            ))
        # One match
        elif num_matches == 1:
            selection = matches[0]
        # Multiple matches
        else:
            # look for an exact match
            selection = _exact_match(response, matches, insensitive, fuzzy)
            # Multiple matches left
            if selection is None:
                stream.write("[!] \"{response}\" matches multiple choices:\n".format(
                    response=response
                ))
                for match in matches:
                    stream.write("[!]   {}\n".format(match))
                stream.write("[!] Please specify your choice further.\n")
    return selection