code: def _replace_placeholder(sql_statement, variable):
          
          (variable_name, variable_type, variable_value) = variable
  
          sql_value = RdbmsConnection._expand_placeholder_value(variable_value) if variable_type == PlaceholderType.simple_list \
              else ','.join([ '(%s)' % RdbmsConnection._expand_placeholder_value(v) for v in variable_value ])
  
          return re.sub(PATTERN_SQL_PLACEHOLDER_EXPRESSIONS[variable_type] % variable_name, sql_value, sql_statement)
docs: Return the string obtained by replacing the specified placeholders by
          its corresponding value.
  
  
          @param sql_statement: the string expression of a SQL statement to
              replace placeholders with their corresponding values.
  
          @param variable: the variable to use to replace the corresponding
              placeholder(s) in the SQL statement.
  
              * ``name``: name of the variable.
  
              * ``type``: an instance of ``PlaceholderType``.
  
              * ``value``: the value of this variable to replace the corresponding
                placeholder(s) of this variable in the SQL statement.
  
  
          @return: a string expression of the SQL statement where the
              paceholders of the specified variable have been replace by the
              value of this variable, depending on the type of this varialble.