code: protected Stylesheet resolve(String sheet) {
          try {
              sheet = sheet.replace("\\", "/");
              if (!sheet.endsWith(".scss")) {
                  sheet += ".scss";
              }
  
              try (InputStream is = resolveIntoStream(sheet)) {
                  if (is == null) {
                      warn("Cannot resolve '" + sheet + "'. Skipping import.");
                      return null;
                  }
  
                  Parser p = new Parser(sheet, new InputStreamReader(is));
                  return p.parse();
              }
          } catch (ParseException e) {
              warn(String.format("Error parsing: %s%n%s", sheet, e.toString()));
          } catch (Exception e) {
              warn(String.format("Error importing: %s: %s (%s)", sheet, e.getMessage(), e.getClass().getName()));
          }
          return null;
      }
docs: Resolves a given name into a template.
  <p>
  By default the classloader is used to resolve the template. Also .scss or _ are added as post-/prefix
  if required.
  
  @param sheet the name of the file to resolve
  @return the resolved stylesheet or <tt>null</tt> if the file is not found