title: check if the map has a specific string in it's keys, then give me it's value, that belong this key, Dart
body: <p>may i ask how to check if the map of String,String has in it's keys a specific String
  then i want to get the value that belong this specific key that contains the target String.
  for example
  this Map</p>
  <pre><code>Map&lt;String, String&gt; ListFinalAllInfos = {'stackoverflow': 'one', 'google': 'two'};
  </code></pre>
  <p>and i want to check if this map has this String in it's keys</p>
  <pre><code>stackoverflow
  </code></pre>
  <p>if stackoverflow exists as a key inside the map then i want to get the value
  which is</p>
  <pre><code>one
  </code></pre>
  <p>without converting the map to a list, if this possible.
  thanks in advance</p>