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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 fetch(bank, key, cachedir=None):
    '''
    Fetch data from a salt.cache bank.

    CLI Example:

    .. code-block:: bash

        salt-run cache.fetch cloud/active/ec2/myec2 myminion cachedir=/var/cache/salt/
    '''
    if cachedir is None:
        cachedir = __opts__['cachedir']

    try:
        cache = salt.cache.Cache(__opts__, cachedir=cachedir)
    except TypeError:
        cache = salt.cache.Cache(__opts__)
    return cache.fetch(bank, key)