ty subsequence is
    returned in the result for each pair of consecutive elements
    satisfying the <code>isSeparator</code> predicate and for each element at the
    start or end of the sequence satisfying the <code>isSeparator</code> predicate.
    If <code>true</code>, only nonempty subsequences are returned. The default
    value is <code>true</code>.
  <strong>isSeparator:</strong> A closure that returns <code>true</code> if its argument should be
    used to split the sequence; otherwise, <code>fals