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Defined Contribution Plan (Details) - USD ($)
12 Months Ended
Jul. 31, 2021
Jul. 31, 2020
Defined Contribution Plan (Details) [Line Items]    
Cost contribution $ 39,000 $ 41,000
Class B Common Stock [Member]    
Defined Contribution Plan (Details) [Line Items]    
Cash contributions 6,572 26,193