code: def simplify_gamma_expression(expression):
      extracted_expr, residual_expr = extract_type_tens(
          expression, GammaMatrix
      )
      res_expr = _simplify_single_line(extracted_expr)
      return res_expr * residual_expr
  
file_path: sympy/sympy/physics/hep/gamma_matrices.py
imports: from sympy.core.mul import Mul
  from sympy.core.singleton import S
  from sympy.matrices.dense import eye
  from sympy.matrices.expressions.trace import trace
  from sympy.tensor.tensor import TensorIndexType, TensorIndex, TensMul, TensAdd, tensor_mul, Tensor, TensorHead, TensorSymmetry
label_desc: Use image node_id 2 for calling a global function with example usage: simplify_gamma_expression(expression) and returns: unknown