def __init__(self, package, version):
        """Construct a new requirement.

        :param package: the package name.
        :param version: a semver compatible version specification.
        """
        self.package = package
        self.version = version
        if self.version and not re.match(r"[<=>~]", version[:2]):
            self.version = "=={}".format(self.version)
def __init__(
        self,
        new_item_default_value,
        min_size=0,
        max_size=None,
        item_spacing=ItemBox.ITEM_SPACING,
        max_width=None,
        max_height=None,
        *args,
        **kwargs):
    """
    Parameters: