This function extracts valid headers from interactive input.

def extract_headers(headers):
    """This function extracts valid headers from interactive input."""
    sorted_headers = {}
    matches = re.findall(r'(.*):\s(.*)', headers)
    for match in matches:
        header = match[0]
        value = match[1]
        try:
            if value[-1] == ',':
                value = value[:-1]
            sorted_headers[header] = value
        except IndexError:
            pass
    return sorted_headers