# Codeblock 2a
class ConvNeXtBlock(nn.Module):
    def __init__(self, num_channels):         #(1)
        super().__init__()
        hidden_channels = num_channels * 4    #(2)

        
        self.conv0 = nn.Conv2d(in_channels=num_channels,         #(3) 
                               out_channels=num_channels,        #(4)
                               kernel_size=7,    #(5)
                               stride=1,
                               padding=3,        #(6)
                               groups=num_channels)              #(7)
        
        self.norm = nn.LayerNorm(normalized_shape=num_channels)  #(8)
        
        self.conv1 = nn.Conv2d(in_channels=num_channels,         #(9)
                               out_channels=hidden_channels, 
                               kernel_size=1, 
                               stride=1, 
                               padding=0)
        
        self.gelu = nn.GELU()  #(10)
        
        self.conv2 = nn.Conv2d(in_channels=hidden_channels,      #(11)
                               out_channels=num_channels, 
                               kernel_size=1, 
                               stride=1, 
                               padding=0)