code: def _prepare_statement(sql_statement, parameters):
          
          placehoolders = RdbmsConnection._get_placeholders(sql_statement, parameters)
  
          for (variable_name, (variable_type, variable_value)) in placehoolders.iteritems():
              # Only expand parameters whose value corresponds to a list.
              if isinstance(variable_value, (list, set, tuple)):
                  sql_statement = RdbmsConnection._replace_placeholder(sql_statement,
                          (variable_name, variable_type, variable_value))
  
                  # Remove this parameter as it has been expended in the SQL expression.
                  del parameters[variable_name]
  
          return sql_statement
docs: Prepare the specified SQL statement, replacing the placeholders by the
          value of the given parameters
  
          @param sql_statement: the string expression of a SQL statement.
  
          @param parameters: a dictionary of parameters where the key represents
              the name of a parameter and the value represents the value of this
              parameter to replace in each placeholder of this parameter in the
              SQL statement.
  
  
          @return: a string representation of the SQL statement where the
              placehodlers have been replaced by the value of the corresponding
              variables, depending on the type of these variables.