code: def get_range_of_selected_signals_on_axis(
      self, axis, selected_signal=None
  ):
      max_val = -float("inf")
      min_val = float("inf")
      for signal in self.signals.values():
          if (selected_signal and signal.name == selected_signal) or (
              signal.selected and signal.axis == axis
          ):
              max_val = max(max_val, signal.max_val)
              min_val = min(min_val, signal.min_val)
      return min_val, max_val
  
file_path: coach/rl_coach/dashboard_components/signals_file_base.py
imports: import numpy
  from bokeh.models import ColumnDataSource
  from rl_coach.dashboard_components.signals import Signal
  from rl_coach.dashboard_components.globals import x_axis, x_axis_options, show_spinner
label_desc: Use image node_id 13 for calling the SignalsFileBase obj's underlying member method code with example usage: obj.get_range_of_selected_signals_on_axis(axis, selected_signal) and returns: min_val,  max_val