code: public Integer getEstimatedCharsPerLine() {
          if (!dataObj.has(CUSTOM_FIELD_AVG_TEXT_LENGTH)) {
              return null;
          }
          Integer numLines = null;
          try {
              JSONObject obj = dataObj.getJSONObject(CUSTOM_FIELD_AVG_TEXT_LENGTH);
              numLines = obj.getInt(CUSTOM_FIELD_NUM_CHARS_PER_LINE);
          } catch (JSONException e) {
          }
          return numLines;
      }
docs: Once processed with a position, height, and width, HelloSign will
  estimate the number of lines a custom field can contain, along with the
  number of characters per line. This method will return the estimated
  average number of characters per line this field can hold.
  
  @return Integer or null if not set