code: def _get_columns(self, blueprint):
          
          columns = []
  
          for column in blueprint.get_added_columns():
              sql = self.wrap(column) + ' ' + self._get_type(column)
  
              columns.append(self._add_modifiers(sql, blueprint, column))
  
          return columns
docs: Get the blueprint's columns definitions.
  
          :param blueprint: The blueprint
          :type blueprint: Blueprint
  
          :rtype: list