class_docstr: Constructor for actually creating things
code: def __call__(self, *args):
      c = args[0]
      if isinstance(c, list):
          letter, n = c[0], int(c[1])
      elif isinstance(c, str):
          letter, n = c[0], int(c[1:])
      else:
          raise TypeError(
              "Argument must be a string (e.g. 'A3') or a list (e.g. ['A', 3])"
          )
  
      if n < 0:
          raise ValueError("Lie algebra rank cannot be negative")
      if letter == "A":
          from . import type_a
  
          return type_a.TypeA(n)
      if letter == "B":
          from . import type_b
  
          return type_b.TypeB(n)
  
      if letter == "C":
          from . import type_c
  
          return type_c.TypeC(n)
  
      if letter == "D":
          from . import type_d
  
          return type_d.TypeD(n)
  
      if letter == "E":
          if n >= 6 and n <= 8:
              from . import type_e
  
              return type_e.TypeE(n)
  
      if letter == "F":
          if n == 4:
              from . import type_f
  
              return type_f.TypeF(n)
  
      if letter == "G":
          if n == 2:
              from . import type_g
  
              return type_g.TypeG(n)
  
file_path: sympy/sympy/liealgebras/cartan_type.py
imports: from sympy.core import Atom, Basic
label_desc: Use image node_id 1 for calling the CartanType_generator obj's underlying member method code with example usage: obj.__call__() and returns: type_a, type_b, type_c, type_d, type_e, type_f, type_g