input: from typing import List
  
  def crud_operations_implemented(code: str) -> bool:
      """ Check if the given Python code correctly implements the standard CRUD functionality 
      as specified in the provided instruction.
      >>> crud_operations_implemented("""import sqlite3
      ...
      ... class Model:
      ...
      ...   def __init__(self):
      ...     self.conn = sqlite3.connect(":memory:")
      ...     self.cursor = self.conn.cursor()
      ...
      ...   def create(self,name):
      ...     self.cursor.execute(
      ...       "CREATE TABLE IF NOT EXISTS Models (name TEXT)"
      ...     )
      ...     self.cursor.execute(
      ...       "INSERT INTO Models(name) VALUES (?)",
      ...       (name,),
      ...     )
      ...     self.conn.commit()
      ...
      ...   def read(self):
      ...     self.cursor.execute("SELECT * FROM Models")
      ...     return self.cursor.fetchall()
      ...
      ...   def update(self,name):
      ...     self.cursor.execute(
      ...       "UPDATE Models SET name = ? WHERE name = ?", 
      ...       (name, name,),
      ...     )
      ...     self.conn.commit()
      ...  
      ...   def delete(self, name):
      ...     self.cursor.execute(
      ...       "DELETE FROM Models WHERE name = ?",
      ...       (name,),
      ...     )
      ...     self.conn.commit()""")
      True
      """
output:     import ast
      class CRUDChecker(ast.NodeVisitor):
          def __init__(self):
              self.has_create = False
              self.has_read = False
              self.has_update = False
              self.has_delete = False
  
          def visit_ClassDef(self, node):
              for stmt in node.body:
                  if isinstance(stmt, ast.FunctionDef):
                      if stmt.name == 'create':
                          self.has_create = True
                      elif stmt.name == 'read':
                          self.has_read = True
                      elif stmt.name == 'update':
                          self.has_update = True
                      elif stmt.name == 'delete':
                          self.has_delete = True
              self.generic_visit(node)
  
      tree = ast.parse(code)
      checker = CRUDChecker()
      checker.visit(tree)
  
      return checker.has_create and checker.has_read and checker.has_update and checker.has_delete