from typing import Sequence
from typing import Any
from typing import List


def _space_list(list_: Sequence[Any]) -> List[str]:
    """ Inserts whitespace between adjacent non-whitespace tokens. """
    spaced_statement: List[str] = []
    for i in reversed(range(len(list_))):
        spaced_statement.insert(0, list_[i])
        if i > 0 and not list_[i].isspace() and not list_[i-1].isspace():
            spaced_statement.insert(0, " ")
    return spaced_statement