anchor.diff:  
   (defun hash-list-remove-columns (hash-list &rest columns)
     (loop for hash in hash-list
  -     do (loop for column in columns
  -           do (remhash column hash))))
  +     when (loop for column in columns
  +             thereis (remhash column hash))
  +     summing 1))
  +
   
   (defun hash-list-first-index-of (hash-list &rest key-value-pairs)
     (loop for row in hash-list
  
positive.code:      summing 1))
  
  (defun hash-list-keys (hash-list)
    "This function returns a list of the keys that are present in every element of the list"
    (loop with counts = (make-hash-table :test 'equal)
       for hash in hash-list
       do (loop for key being the hash-keys in hash
  
negative.code:             (/ (float et) 3600)
              (/ (float rt) 3600)
              (timestamp :time (truncate eta) :format "h:m:s"))))
  
  