 class="keyword">val</span>&nbsp;read&nbsp;:&nbsp;string&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;string<br>
&nbsp;&nbsp;<span class="keyword">val</span>&nbsp;write&nbsp;:&nbsp;string&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;string&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;unit<br>
&nbsp;&nbsp;<span class="keyword">val</span>&nbsp;remove&nbsp;:&nbsp;string&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;unit<br>
&nbsp;&nbsp;<span class="keyword">val</span>&nbsp;remove_file&nbsp;:&nbs