Secondary Loss Event Frequency PERT input values should be between 0 and 1

[vidhisshah]

Similar to the validation checks in place for 'Probability of Action', 'Vulnerability', 'Control Strength', 'Threat Capability', there probably should be a check in place for Secondary Loss Event Frequency as well. The value will eventually be multiplied with Loss Event Frequency, so it should be less than or equal to one, more specifically between zero and one.

I looked through some other issues, to see if others are using it as I am, and they are. (Example issue 17)

[theonaunheim]

Thanks for the issue, @vidhisshah . You are correct: this is how it is intended to be used and should be validated.

Will tweak the master_fix branch and send an update this weekend.