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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 format_attrs(attrs):
 """ Format key, value pairs from attrs into graphviz attrs format Examples -------- '[key1=value1, key2=value2]' """

    if not attrs:
        return ''
    entries = ['='.join((key, value)) for key, value in iteritems(attrs)]
    return '[' + ', '.join(entries) + ']'