code: def call_sql(sql_expression: str) -> Expression:
      """
      A call to a SQL expression.
  
      The given string is parsed and translated into a Table API expression during planning. Only
      the translated expression is evaluated during runtime.
  
      Note: Currently, calls are limited to simple scalar expressions. Calls to aggregate or
      table-valued functions are not supported. Sub-queries are also not allowed.
  
      :param sql_expression: SQL expression to be translated
      """
      return _unary_op("callSql", sql_expression)
  
imports: from typing import Union
  from pyflink import add_version_doc
  from pyflink.java_gateway import get_gateway
  from pyflink.table.expression import Expression, _get_java_expression, TimePointUnit, JsonOnNull
  from pyflink.table.types import _to_java_data_type, DataType
  from pyflink.table.udf import UserDefinedFunctionWrapper
  from pyflink.util.java_utils import to_jarray, load_java_class
label_desc: Use image node_id 58 for calling a global function with example usage: call_sql(sql_expression) and returns: _unary_op