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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def from_value(cls, ion_type, value, annotations=()):
 """Constructs a value as a copy with an associated Ion type and annotations. Args: ion_type (IonType):
 The associated Ion type. value (Any):
 The value to construct from, generally of type ``cls``. annotations (Sequence[unicode]):
 The sequence Unicode strings decorating this value. """

        if value is None:
            value = IonPyNull()
        else:
            args, kwargs = cls._to_constructor_args(value)
            value = cls(*args, **kwargs)
        value.ion_event = None
        value.ion_type = ion_type
        value.ion_annotations = annotations
        return value