docs: @Nullable
      static String shaHashInput(@Nullable String toHash) {
          if (StripeTextUtils.isBlank(toHash)) {
              return null;
          }
  
          try {
              final MessageDigest digest = MessageDigest.getInstance("SHA-1");
              final byte[] bytes = toHash.getBytes("UTF-8");
              digest.update(bytes, 0, bytes.length);
              return bytesToHex(digest.digest());
          } catch (NoSuchAlgorithmException noSuchAlgorithm) {
              return null;
          } catch (UnsupportedEncodingException unsupportedCoding) {
              return null;
          }
      }