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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 finger_master(hash_type=None):
    '''
    Return the fingerprint of the master's public key

    hash_type
        The hash algorithm used to calculate the fingerprint

    .. code-block:: python

        >>> wheel.cmd('key.finger_master')
        {'local': {'master.pub': '5d:f6:79:43:5e:d4:42:3f:57:b8:45:a8:7e:a4:6e:ca'}}
    '''
    keyname = 'master.pub'
    if hash_type is None:
        hash_type = __opts__['hash_type']

    fingerprint = salt.utils.crypt.pem_finger(
        os.path.join(__opts__['pki_dir'], keyname), sum_type=hash_type)
    return {'local': {keyname: fingerprint}}