def subtype(self, value=noValue, **kwargs):
        """Create a specialization of |ASN.1| schema or value object.

        The subtype relationship between ASN.1 types has no correlation with
        subtype relationship between Python types. ASN.1 type is mainly identified
        by its tag(s) (:py:class:`~pyasn1.type.tag.TagSet`) and value range
        constraints (:py:class:`~pyasn1.type.constraint.ConstraintsIntersection`).
        These ASN.1 type properties are implemented as |ASN.1| attributes.  

        The `subtype()` method accepts the same set arguments as |ASN.1|
        class takes on instantiation except that all parameters
        of the `subtype()` method are optional.

        With the exception of the arguments described below, the rest of
        supplied arguments they are used to create a copy of `self` taking
        precedence over the ones used to instantiate `self`.

        The following arguments to `subtype()` create a ASN.1 subtype out of
        |ASN.1| type:

        Other Parameters
        ----------------
        implicitTag: :py:class:`~pyasn1.type.tag.Tag`
            Implicitly apply given ASN.1 tag object to `self`'s
            :py:class:`~pyasn1.type.tag.TagSet`, then use the result as
            new object's ASN.1 tag(s).

        explicitTag: :py:class:`~pyasn1.type.tag.Tag`
            Explicitly apply given ASN.1 tag object to `self`'s
            :py:class:`~pyasn1.type.tag.TagSet`, then use the result as
            new object's ASN.1 tag(s).

        subtypeSpec: :py:class:`~pyasn1.type.constraint.ConstraintsIntersection`
            Add ASN.1 constraints object to one of the `self`'s, then
            use the result as new object's ASN.1 constraints.

        Returns
        -------
        :
            new instance of |ASN.1| schema or value object

        Note
        ----
        Due to the immutable nature of the |ASN.1| object, if no arguments
        are supplied, no new |ASN.1| object will be created and `self` will
        be returned instead.
        """
        if value is noValue:
            if not kwargs:
                return self

            value = self._value

        initializers = self.readOnly.copy()

        implicitTag = kwargs.pop('implicitTag', None)
        if implicitTag is not None:
            initializers['tagSet'] = self.tagSet.tagImplicitly(implicitTag)

        explicitTag = kwargs.pop('explicitTag', None)
        if explicitTag is not None:
            initializers['tagSet'] = self.tagSet.tagExplicitly(explicitTag)

        for arg, option in kwargs.items():
            initializers[arg] += option

        return self.__class__(value, **initializers)