def _stack_exists(cf_client, stack_name):
    """Determine if the stack already exists.

    Parameters
    ----------
    stack_name : str
        Name of the stack to find.

    Returns
    -------
    bool
        True if the stack already exists.
    """
    stacks = cf_client.list_stacks()['StackSummaries']
    for stack in stacks:
        if stack['StackStatus'] == 'DELETE_COMPLETE':
            continue
        if stack_name == stack['StackName']:
            return True
    return False
