code: def test_OneMatrix():
      n, m = symbols("n m", integer=True)
      A = MatrixSymbol("A", n, m)
      U = OneMatrix(n, m)
  
      assert U.shape == (n, m)
      assert isinstance(A + U, Add)
      assert U.transpose() == OneMatrix(m, n)
      assert U.conjugate() == U
      assert U.adjoint() == OneMatrix(m, n)
      assert re(U) == U
      assert im(U) == ZeroMatrix(n, m)
  
      assert OneMatrix(n, n) ** 0 == Identity(n)
  
      U = OneMatrix(n, n)
      assert U[1, 2] == 1
  
      U = OneMatrix(2, 3)
      assert U.as_explicit() == ImmutableDenseMatrix.ones(2, 3)
  
imports: from sympy.core.add import Add
  from sympy.core.expr import unchanged
  from sympy.core.mul import Mul
  from sympy.core.symbol import symbols
  from sympy.core.relational import Eq
  from sympy.concrete.summations import Sum
  from sympy.functions.elementary.complexes import im, re
  from sympy.functions.elementary.piecewise import Piecewise
  from sympy.matrices.immutable import ImmutableDenseMatrix
  from sympy.matrices.expressions.matexpr import MatrixSymbol
  from sympy.matrices.expressions.matadd import MatAdd
  from sympy.matrices.expressions.special import ZeroMatrix, GenericZeroMatrix, Identity, GenericIdentity, OneMatrix
  from sympy.matrices.expressions.matmul import MatMul
  from sympy.testing.pytest import raises
label_desc: Use image node_id 8 for calling a global function with example usage: test_OneMatrix() without return types