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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 exists(stream_name, region=None, key=None, keyid=None, profile=None):
    '''
    Check if the stream exists. Returns False and the error if it does not.

    CLI example::

        salt myminion boto_kinesis.exists my_stream region=us-east-1
    '''
    conn = _get_conn(region=region, key=key, keyid=keyid, profile=profile)
    r = {}

    stream = _get_basic_stream(stream_name, conn)
    if 'error' in stream:
        r['result'] = False
        r['error'] = stream['error']
    else:
        r['result'] = True

    return r