docstr: Add another channel to the channels list
docstr_tok: ["Add","another","channel","to","the","channels","list"]
code: def add_channel(self, can_remove=True):
      """Add another channel to the channels list"""
      group = SettingsGroup()
      group.can_remove = can_remove
      group.append(
          "channel_choice",
          Integer(
              text="Channel number",
              value=len(self.channels) + 1,
              minval=1,
              doc="""\
  *(Used only when splitting images)*
  
  This setting chooses a channel to be processed. For example, *1*
  is the first
  channel in a .TIF or the red channel in a traditional image file.
  *2* and *3* are the second and third channels of a TIF or
  the green and blue channels in other formats. *4* is the
  transparency channel for image formats that support transparency and is
  channel # 4 for a .TIF file. **ColorToGray** will fail to process an
  image if you select a channel that is not supported by that image, for
  example, “5” for a three-channel .PNG file.""",
          ),
      )
  
      group.append(
          "contribution",
          Float(
              "Relative weight of the channel",
              1,
              0,
              doc="""\
  *(Used only when combining channels)*
  
  Relative weights: If all relative weights are equal, all three colors
  contribute equally in the final image. To weight colors relative to each
  other, increase or decrease the relative weights.""",
          ),
      )
  
      group.append(
          "image_name",
          ImageName(
              "Image name",
              value="Channel%d" % (len(self.channels) + 1),
              doc="""\
  *(Used only when splitting images)*
  
  Select the name of the output grayscale image.""",
          ),
      )
  
      if group.can_remove:
          group.append(
              "remover",
              RemoveSettingButton(
                  "", "Remove this channel", self.channels, group
              ),
          )
      self.channels.append(group)
  
imports: import re
  import matplotlib.colors
  import numpy
  from cellprofiler_core.image import Image
  from cellprofiler_core.module import Module
  from cellprofiler_core.setting import Binary
  from cellprofiler_core.setting import HiddenCount
  from cellprofiler_core.setting import SettingsGroup
  from cellprofiler_core.setting import ValidationError
  from cellprofiler_core.setting.choice import Choice
  from cellprofiler_core.setting.do_something import DoSomething
  from cellprofiler_core.setting.do_something import RemoveSettingButton
  from cellprofiler_core.setting.subscriber import ImageSubscriber
  from cellprofiler_core.setting.text import Float
  from cellprofiler_core.setting.text import ImageName
  from cellprofiler_core.setting.text import Integer
label_desc: Use image node_id 2 for calling the ColorToGray obj's underlying member method code with example usage: obj.add_channel(can_remove) without return types