I am struggling with this challenge and have been for quite some time. I am not sure what I am missing so any help would be appreciated. 

I am getting the following error:

Challenge Not yet complete... here's what's wrong: 
We can't find the 'Create Seed Bank' node or required fields, such as 'TempClass', are missing. Check the challenge and confirm the node name and required fields.

Here is my JSON:

{
  "Add Temp Class": {
    "action": "computeExpression",
    "parameters": {
      "source": "Define Temp Range",
      "mergeWithSource": true,
      "computedFields": [
        {
          "defaultValue": "Continental",
          "name": "TempClass",
          "saqlExpression": "case \nwhen LowTemp < 25 and HighTemp < 25 then \"Polar\" \nwhen LowTemp >= 25 and LowTemp <= 50 and HighTemp >= 25 and HighTemp <= 50 then \"Cool\"\nwhen LowTemp >= 51 and LowTemp <= 85 and HighTemp >= 51 and HighTemp <= 85 then \"Continental\"\nwhen LowTemp > 85 and HighTemp > 85 then \"Tropical\"\nwhen LowTemp < 25 and (HighTemp >= 25 and HighTemp <= 50) then \"Polar-Cool\" \nwhen LowTemp < 25 and (HighTemp >= 25 and HighTemp <= 85) then \"Polar-Cool-Continental\" \nwhen LowTemp < 25 and HighTemp > 85 then \"Polar-Cool-Continental-Tropical\" \nwhen (LowTemp >= 25 and LowTemp <= 50) and (HighTemp >= 51 and HighTemp <= 85) then \"Cool-Continental\" \nwhen (LowTemp >= 25 and LowTemp <= 50) and HighTemp >= 85 then \"Cool-Continental-Tropical\" \nwhen (LowTemp >= 51 and LowTemp <= 85) and HighTemp > 85 then \"Continental-Tropical\" \nend",
          "label": "TempClass",
          "type": "Text"
        }
      ]
    }
  },
  "Calculate Acreage": {
    "action": "computeExpression",
    "parameters": {
      "source": "Load Seed Chart",
      "mergeWithSource": true,
      "computedFields": [
        {
          "precision": 18,
          "name": "Acreage",
          "saqlExpression": "(Seeds_Pound*Spacing)/6272640",
          "scale": 6,
          "label": "Acreage",
          "type": "Numeric"
        }
      ]
    }
  },
  "Create Seed Bank": {
    "action": "sfdcRegister",
    "parameters": {
      "name": "Seed Bank",
      "alias": "seed_bank",
      "source": "CleanUp"
    }
  },
  "Load Seed Chart": {
    "action": "edgemart",
    "parameters": {
      "alias": "Seed_Chart"
    }
  },
  "Augment Temp Class": {
    "action": "augment",
    "parameters": {
      "left": "Add Temp Class",
      "right": "Load Temp Class Mapping",
      "relationship": "Climate",
      "operation": "LookupMultiValue",
      "left_key": [
        "TempClass"
      ],
      "right_key": [
        "TempKey"
      ],
      "right_select": [
        "TempKey"
      ]
    }
  },
  "Load Temp Class Mapping": {
    "action": "edgemart",
    "parameters": {
      "alias": "Temperature_Classes_Mapping"
    }
  },
  "CleanUp": {
    "action": "sliceDataset",
    "parameters": {
      "mode": "drop",
      "source": "Augment Temp Class",
      "fields": [
        {
          "name": "LowTemp"
        },
        {
          "name": "HighTemp"
        }
      ]
    }
  },
  "Define Temp Range": {
    "action": "computeExpression",
    "parameters": {
      "source": "Calculate Acreage",
      "mergeWithSource": true,
      "computedFields": [
        {
          "defaultValue": "0",
          "precision": 18,
          "name": "LowTemp",
          "saqlExpression": "string_to_number(substr(Temperature,1,2))",
          "scale": 2,
          "label": "LowTemp",
          "type": "Numeric"
        },
        {
          "defaultValue": "0",
          "precision": 18,
          "name": "HighTemp",
          "saqlExpression": "string_to_number(substr(Temperature,3,3))",
          "scale": 2,
          "label": "HighTemp",
          "type": "Numeric"
        }
      ]
    }
  }
}
Thanks in advance