text: import dash
  from dash import dependencies as dep
  import dash_core_components as dcc
  import dash_html_components as html
  
  from . import bivariate, univariate
  
  
  LOGO = html.Img(
      src="https://camo.githubusercontent.com/2af4bb9d3ff6744a6ad1aab0b2b916b5efee8b49/68747470733a2f2f63646e2e7261776769742e636f6d2f70796d632d646576732f70796d63332f6d61737465722f646f63732f6c6f676f732f7376672f50794d43335f62616e6e65722e737667",
      width=300
  )
  
  HEADER = html.Div([
      html.Table([
          html.Tr([
              html.Td([
                  LOGO,
              ]),
              html.Td([
                  dcc.Link("Univariate", href='/univariate'),
              ]),
              html.Td([
                  dcc.Link("Bivariate", href='/bivariate'),
              ])
          ]),
      ]),
      html.Hr()
  ])
  
  
  LAYOUT = html.Div([
      dcc.Location(id='url', refresh=False),
      HEADER,
      html.Div(id='page-content')
  ])
  
  
  def add_callbacks(app, trace_info):
      bivariate_layout = bivariate.layout(trace_info)
      univariate_layout = univariate.layout(trace_info)
  
      @app.callback(
          dep.Output('page-content', 'children'),
          [dep.Input('url', 'pathname')]
      )
      def update_page_content(pathname):
          if pathname in ['/', '/univariate']:
              return univariate_layout
          elif pathname == '/bivariate':
              return bivariate_layout
  
      bivariate.add_callbacks(app, trace_info)
      univariate.add_callbacks(app, trace_info)
  