input: Write a function to perform basic calculator operations using lambda functions.
  assert calculate(10, '+', 5) == 15
  assert calculate(10, '-', 5) == 5
  assert calculate(10, '*', 5) == 50
  assert calculate(10, '/', 5) == 2
  assert calculate(10, '/', 0) == "Division by zero error"
output: def calculate(a, operator, b):
      operations = {
          '+': lambda x, y: x + y,
          '-': lambda x, y: x - y,
          '*': lambda x, y: x * y,
          '/': lambda x, y: x / y if y != 0 else "Division by zero error"
      }
      return operations[operator](a, b)