class_docstr: This class contains the information about
  the A series of simple Lie algebras.
  ====
code: def __new__(cls, n):
      if n < 1:
          raise ValueError("n cannot be less than 1")
      return Standard_Cartan.__new__(cls, "A", n)
  
file_path: sympy/sympy/liealgebras/type_a.py
imports: from sympy.liealgebras.cartan_type import Standard_Cartan
  from sympy.core.backend import eye
label_desc: Use image node_id 1 for calling the TypeA obj's underlying member method code with example usage: obj.__new__(cls, n) and returns: Standard_Cartan