Checking conditions unrelated to expression

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It looks like pcase can only be used with some variable condition

This will check condition of featr

  (pcase featr
     ('this (do-this))
     ('that (do-that))
     (_ (message "some message"))

What if I want to check a number of conditions, not all dependent upon
featr, what should one do? 

Suppose I want to test (eq duck 'quack), cannot use a pcase because tests
are dependent upon featr.

  (pcase featr
     ('this (do-this))
     ('that (do-that))
     (_ (message "some message"))