7. Fair Value Measurements and Derivative Liabilities: Schedule of Assumptions Used (Details)	9 Months Ended
	Jan. 31, 2020
Fair Value Assumptions, Risk Free Interest Rate	0.0200
Fair Value Assumptions, Expected Dividend Rate	0.0000
Fair Value Assumptions, Expected Volatility Rate	4.4300
Minimum
Fair Value Assumptions, Expected Term	3 months
Maximum
Fair Value Assumptions, Expected Term	10 months 6 days