input: Write a function to generate a data visualization dashboard using Matplotlib in Python. The function should create a simple plot with given data and display it. If no data is provided, the function should display an empty plot with default settings.
  assert create_dashboard([[1,2,3,4,5], [10,25,30,50,80]])==None
  assert create_dashboard([])==None
output: def create_dashboard(data=None):
      import matplotlib.pyplot as plt
      if data:
          x, y = data
          plt.plot(x, y)
      else:
          plt.plot()
      plt.show()