Prompt `username` for password.

    Parameters
    ----------
    username: str
        name of the TissueMAPS user

    Returns
    -------
    str
        password for the given user

def prompt_for_credentials(username):
    '''Prompt `username` for password.

    Parameters
    ----------
    username: str
        name of the TissueMAPS user

    Returns
    -------
    str
        password for the given user

    '''
    message = 'Enter password for user "{0}": '.format(username)
    password = getpass.getpass(message)
    if not password:
        raise ValueError(
            'No credentials provided for user "{0}"'.format(username)
        )
    return password