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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 as_tuple(self, named=None):
 """ Create a structured schema that will pass stream tuples into callables as ``tuple`` instances. If this instance represents a common schema then it will be returned without modification. Stream tuples with common schemas are always passed according to their definition. **Passing as tuple** When `named` evaluates to ``False`` then each stream tuple will be passed as a ``tuple``. For example with a structured schema of ``tuple<rstring id, float64 value>`` a value is passed as ``('TempSensor', 27.4)`` and access to the first attribute is ``t[0]`` and the second as ``t[1]`` where ``t`` represents the passed value.. **Passing as named tuple** When `named` is ``True`` or a ``str`` then each stream tuple will be passed as a named tuple. For example with a structured schema of ``tuple<rstring id, float64 value>`` a value is passed as ``('TempSensor', 27.4)`` and access to the first attribute is ``t.id`` (or ``t[0]``) and the second as ``t.value`` (``t[1]``) where ``t`` represents the passed value. .. warning:: If an schema's attribute name is not a valid Python identifier or starts with an underscore then it will be renamed as positional name ``_n``. For example, with the schema ``tuple<int32 a, int32 def, int32 id>`` the field names are ``a``, ``_1``, ``_2``. The value of `named` is used as the name of the named tuple class with ``StreamTuple`` used when `named` is ``True``. It is not guaranteed that the class of the namedtuple is the same for all callables processing tuples with the same structured schema, only that the tuple is a named tuple with the correct field names. Args: named: Pass stream tuples as a named tuple. If not set then stream tuples are passed as instances of ``tuple``. Returns: StreamSchema: Schema passing stream tuples as ``tuple`` if allowed. .. versionadded:: 1.8 .. versionadded:: 1.9 Addition of `named` parameter. """

        if not named:
            return self._copy(tuple)

        if named == True or isinstance(named, basestring):
            return self._copy(self._make_named_tuple(name=named))

        return self._copy(tuple)