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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 get_policy_definitions(settings):
 """Find all multiauth policy definitions from the settings dict. This function processes the paster deployment settings looking for items that start with "multiauth.policy.<policyname>.". It pulls them all out into a dict indexed by the policy name. """

    policy_definitions = {}
    for name in settings:
        if not name.startswith("multiauth.policy."):
            continue
        value = settings[name]
        name = name[len("multiauth.policy."):]
        policy_name, setting_name = name.split(".", 1)
        if policy_name not in policy_definitions:
            policy_definitions[policy_name] = {}
        policy_definitions[policy_name][setting_name] = value
    return policy_definitions