input: Write a python function to evaluate a given mathematical expression containing 'x' and 'y'.
  assert evaluate_expr("((x+y)^2)*(x+1)", 2, 3) == 125.0
  assert evaluate_expr("(x+y)*y", 1, 2) == 6.0
  assert evaluate_expr("x^2 + y^2", 3, 4) == 25.0
output: def evaluate_expr(expression, x, y):
      # Replace '^' with '**' for exponentiation
      expression = expression.replace('^', '**')
      # Evaluate the expression using eval()
      result = eval(expression, {"x": x, "y": y})
      return float(result)