Introductory it as Object
Pattern group 4: V it n clause
There are three patterns in this group, each consisting of the verb, it, a noun group, and a type of clause.4.1 V it n that
I thought it a pity that she didn't get the job.4.2 V it n to-inf
They felt it their duty to visit her in hospital.4.3 V it n when/if
I'd consider it a compliment if you accepted.