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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 delete(workflow_id: str = None, workflow_version: str = None):
 """Delete workflow definitions. Args: workflow_id (str, optional):
 Optional workflow identifier workflow_version (str, optional):
 Optional workflow identifier version If workflow_id and workflow_version are None, delete all workflow definitions. """

    if workflow_id is None and workflow_version is None:
        keys = DB.get_keys("workflow_definitions:*")
        DB.delete(*keys)
    elif workflow_id is not None and workflow_version is None:
        keys = DB.get_keys("workflow_definitions:{}:*".format(workflow_id))
        DB.delete(*keys)
    elif workflow_id is None and workflow_version is not None:
        keys = DB.get_keys("workflow_definitions:*:{}"
                           .format(workflow_version))
        DB.delete(*keys)
    else:
        name = "workflow_definitions:{}:{}".format(workflow_id,
                                                   workflow_version)
        DB.delete(name)