def get_issue(repo, subject, labelList = None, verbose=None):
    """get issue it it already exists.

    Args:
        repo (object): a github.Repository.
        subject (str): Subject line.
        verbose (bool): True turns on verbose.

    Returns:
        github.Issue.Issue
    """
    if not repo :
        raise ValueError("Error:post_issues_to_github: repo is not defined for subject '" +  subject +"'") 
 
    if verbose:
        print("Checking for issue: {0}".format(subject))

    if labelList: 
        issueList = repo.get_issues(state='all',labels=labelList)
    else : 
        issueList = repo.get_issues(state='all')

    for issue in issueList: 
        if issue.title == subject :
            return issue

    return None