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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 pywt_pad_mode(pad_mode, pad_const=0):
 """Convert ODL-style padding mode to pywt-style padding mode. Parameters pad_mode : str The ODL padding mode to use at the boundaries. pad_const : float, optional Value to use outside the signal boundaries when ``pad_mode`` is 'constant'. Only a value of 0. is supported by PyWavelets Returns ------- pad_mode_pywt : str The corresponding name of the requested padding mode in PyWavelets. See `signal extension modes`_. References .. _signal extension modes: https://pywavelets.readthedocs.io/en/latest/ref/signal-extension-modes.html """

    pad_mode = str(pad_mode).lower()
    if pad_mode == 'constant' and pad_const != 0.0:
        raise ValueError('constant padding with constant != 0 not supported '
                         'for `pywt` back-end')
    try:
        return PAD_MODES_ODL2PYWT[pad_mode]
    except KeyError:
        raise ValueError("`pad_mode` '{}' not understood".format(pad_mode))