code: def constant(self, tree):
      for child in tree.children:
          if isinstance(child, Tree):
              if child.data == "real_literal":
                  real_literal = self.visit(child)
                  return ConstantValueExpression(
                      real_literal, ColumnType.FLOAT
                  )
              elif child.data == "decimal_literal":
                  decimal_literal = self.visit(child)
                  return ConstantValueExpression(
                      decimal_literal, ColumnType.INTEGER
                  )
  
      return self.visit_children(tree)
  
imports: import numpy
  from lark import Tree
  from evadb.catalog.catalog_type import ColumnType
  from evadb.expression.abstract_expression import ExpressionType
  from evadb.expression.comparison_expression import ComparisonExpression
  from evadb.expression.constant_value_expression import ConstantValueExpression
  from evadb.expression.logical_expression import LogicalExpression
  from evadb.utils.generic_utils import string_comparison_case_insensitive
label_desc: Use image node_id 4 for calling the Expressions obj's underlying member method code with example usage: obj.constant(tree) and returns: self, ConstantValueExpression, ConstantValueExpression