'create an informative error message if there is an issue authenticating'

def get_auth_error_message(self):

    errors = ['Authentication    error    retrieving    ec2    inventory.']
    if (None in [os.environ.get('AWS_ACCESS_KEY_ID'), os.environ.get('AWS_SECRET_ACCESS_KEY')]):
        errors.append('    -    No    AWS_ACCESS_KEY_ID    or    AWS_SECRET_ACCESS_KEY    environment    vars    found')
    else:
        errors.append('    -    AWS_ACCESS_KEY_ID    and    AWS_SECRET_ACCESS_KEY    environment    vars    found    but    may    not    be    correct')
    boto_paths = ['/etc/boto.cfg', '~/.boto', '~/.aws/credentials']
    boto_config_found = [p for p in boto_paths if os.path.isfile(os.path.expanduser(p))]
    if (len(boto_config_found) > 0):
        errors.append(("    -    Boto    configs    found    at    '%s',    but    the    credentials    contained    may    not    be    correct" % ',    '.join(boto_config_found)))
    else:
        errors.append(("    -    No    Boto    config    found    at    any    expected    location    '%s'" % ',    '.join(boto_paths)))
    return '\n'.join(errors)
