def positive(value):
    """
    Check that the ``value`` is greater than 0.

    Parameters
    ----------
    value: number
        Value to check.

    Raises
    ------
    ValueError
        Raised when ``value`` is not greater than zero.

    Returns
    -------
    success: bool
        Return True.

    """
    if not value > 0:
        raise ValueError(
            'Value {value} should be positive!'
            .format(value=value)
        )

    return True