'Create a copy of a |ASN.1| type or object.
Any parameters to the *subtype()* method will be added to the corresponding
properties of the |ASN.1| object.
Parameters
value: :class:`tuple`, :class:`str` or |ASN.1| object
Initialization value to pass to new ASN.1 object instead of
inheriting one from the caller.
implicitTag: :py:class:`~pyasn1.type.tag.Tag`
Implicitly apply given ASN.1 tag object to caller\'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 caller\'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 caller, then
use the result as new object\'s ASN.1 constraints.
Returns
new instance of |ASN.1| type/value'

def subtype(self, value=noValue, implicitTag=None, explicitTag=None, subtypeSpec=None):

    isModified = False
    if ((value is None) or (value is noValue)):
        value = self._value
    else:
        isModified = True
    if ((implicitTag is not None) and (implicitTag is not noValue)):
        tagSet = self._tagSet.tagImplicitly(implicitTag)
        isModified = True
    elif ((explicitTag is not None) and (explicitTag is not noValue)):
        tagSet = self._tagSet.tagExplicitly(explicitTag)
        isModified = True
    else:
        tagSet = self._tagSet
    if ((subtypeSpec is None) or (subtypeSpec is noValue)):
        subtypeSpec = self._subtypeSpec
    else:
        subtypeSpec = (self._subtypeSpec + subtypeSpec)
        isModified = True
    if isModified:
        return self.__class__(value, tagSet, subtypeSpec)
    else:
        return self
