Function dynamic_technician_available_for_slot 

pub fn dynamic_technician_available_for_slot(
    root: &Value,
    business_id: i64,
    service_id: i64,
    technician_id: i64,
    date_value: &str,
    time_value: &str,
    ignored_appointment_id: i64,
) -> bool

Returns whether one technician may own a service appointment at a requested slot.