docstr: Returns an :obj:`dict` with two keys: "expression_schema", which is
  a schema containing the column names and data types for each valid
  expression in ``expressions``, and "errors", which is a dict of
  expressions to error objects that contain additional metadata:
  `error_message`, `line`, and `column`.
  
  Args:
      expressions (:obj:`list`): A list of string expressions or {name: string, expr: string} objects to validate
          and create a schema from.
  
  Keyword Args:
      as_string (:obj:`bool`): If True, returns the data types as string
          representations so they can be serialized.
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code: def validate_expressions(self, expressions, as_string=False):
      """Returns an :obj:`dict` with two keys: "expression_schema", which is
      a schema containing the column names and data types for each valid
      expression in ``expressions``, and "errors", which is a dict of
      expressions to error objects that contain additional metadata:
      `error_message`, `line`, and `column`.
  
      Args:
          expressions (:obj:`list`): A list of string expressions or {name: string, expr: string} objects to validate
              and create a schema from.
  
      Keyword Args:
          as_string (:obj:`bool`): If True, returns the data types as string
              representations so they can be serialized.
      """
      validated = {
          "expression_schema": {},
          "errors": {},
          "expression_alias": {},
      }
  
      if len(expressions) == 0:
          return validated
  
      expressions = _parse_expression_inputs(expressions)
      validation_results = validate_expressions(
          self._table, expressions
      )
      expression_schema = validation_results.get_expression_schema()
      expression_errors = validation_results.get_expression_errors()
  
      for expression in expressions:
          # expression_alias can be used to map the alias to the
          # full expression string in the UI.
          validated["expression_alias"][expression[0]] = expression[1]
  
      for alias, dtype in expression_schema.items():
          if not as_string:
              dtype = _str_to_pythontype(dtype)
  
          validated["expression_schema"][alias] = expression_schema[
              alias
          ]
  
      for alias, error in expression_errors.items():
          error_dict = {}
          error_dict["error_message"] = error.error_message
          error_dict["line"] = error.line
          error_dict["column"] = error.column
  
          validated["errors"][alias] = error_dict
  
      return validated
  
imports: from datetime import date, datetime
  from ..core.exception import PerspectiveError
  from ._accessor import _PerspectiveAccessor
  from ._callback_cache import _PerspectiveCallBackCache
  from ._date_validator import _PerspectiveDateValidator
  from ._state import _PerspectiveStateManager
  from ._utils import _dtype_to_pythontype, _dtype_to_str, _parse_expression_inputs, _str_to_pythontype
  from .libpsppy import make_table, update_table, str_to_filter_op, t_dtype, t_filter_op, t_op, validate_expressions
  from .view import View
label_desc: Use image node_id 13 for calling the Table obj's underlying member method code with example usage: obj.validate_expressions(expressions, as_string) and returns: validated, validated