code: function normalize(obj) {
      const isMultipart = isFormData(obj);
      const content = { filename: '', value: '', mime: '' };
      const result = ((isMultipart) ? new FormData() : {});
      let file = null;
  
      Object.keys(obj).forEach((item) => {
          if (isMultipart) {
              if (obj[item].value) content.value = obj[item].value;
              else content.value = obj[item];
  
              content.filename = obj[item].filename || null;
              content.mime = obj[item].mime || null;
  
              if (content.value instanceof stream.Stream) {
                  result.append(item, content.value, {
                      contentType: content.mime,
                      filename: content.filename,
                  });
  
                  return;
              }
  
              if (Buffer.isBuffer(content.value)) {
                  file = FileType(content.value);
                  result.append(item, content.value, {
                      contentType: content.mime || file.mime || 'application/octet-stream',
                      filename: content.filename || `data-${Date.now()}.${file.ext || ''}`,
                  });
  
                  return;
              }
  
              if (typeof content.value === 'object') {
                  result.append(item, JSON.stringify(content.value), {
                      contentType: 'application/json',
                  });
  
                  return;
              }
  
              result.append(item, content.value);
          } else {
              if (typeof obj[item] === 'object') {
                  result[item] = JSON.stringify(obj[item]);
                  return;
              }
  
              result[item] = obj[item];
          }
      });
  
      return result;
  }
docs: Normalizes an object to sending into body of the request
  @private
  
  @param  {Object} obj - An object with data for sending
  @return {Object|form-data}