'This method can be called by methods that need a sequence.  If
`mutable` is true, it will also ensure that the response sequence
is a standard Python list.
.. versionadded:: 0.6'

def _ensure_sequence(self, mutable=False):

    if self.is_sequence:
        if (mutable and (not isinstance(self.response, list))):
            self.response = list(self.response)
        return
    if self.direct_passthrough:
        raise RuntimeError('Attempted    implicit    sequence    conversion    but    the    response    object    is    in    direct    passthrough    mode.')
    if (not self.implicit_sequence_conversion):
        raise RuntimeError('The    response    object    required    the    iterable    to    be    a    sequence,    but    the    implicit    conversion    was    disabled.        Call    make_sequence()    yourself.')
    self.make_sequence()
