def coerce(cls, string):
        """Create a :class:`Requirement` object from a given package spec."""
        match = re.match(cls.spec_regex, string)
        if not match:
            raise InvalidRequirementSpecError("could not parse requirement")
        package = match.group(1)
        if all(match.group(2, 3)):
            version = "".join(match.group(2, 3))
        else:
            version = None
        return cls(package, 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: