# lt.population_size fails for wrong input

    argument "e0" is missing, with no default

# lt.population_size produces the right output

    {
      "type": "list",
      "attributes": {
        "names": {
          "type": "character",
          "attributes": {},
          "value": ["method", "value", "description"]
        },
        "class": {
          "type": "character",
          "attributes": {},
          "value": ["data.frame"]
        },
        "row.names": {
          "type": "integer",
          "attributes": {},
          "value": [1, 2, 3, 4, 5]
        }
      },
      "value": [
        {
          "type": "character",
          "attributes": {},
          "value": ["D", "e0", "k", "t", "P"]
        },
        {
          "type": "double",
          "attributes": {},
          "value": [247, 30.7, 1.1, 100, 83.3]
        },
        {
          "type": "character",
          "attributes": {},
          "value": ["Number of deaths", "Life expectancy", "Correction factor", "Time span", "Population size"]
        }
      ]
    }

---

    {
      "type": "list",
      "attributes": {
        "names": {
          "type": "character",
          "attributes": {},
          "value": ["corpus mandibulae", "margo orbitalis"]
        }
      },
      "value": [
        {
          "type": "list",
          "attributes": {
            "names": {
              "type": "character",
              "attributes": {},
              "value": ["method", "value", "description"]
            },
            "class": {
              "type": "character",
              "attributes": {},
              "value": ["data.frame"]
            },
            "row.names": {
              "type": "integer",
              "attributes": {},
              "value": [1, 2, 3, 4, 5]
            }
          },
          "value": [
            {
              "type": "character",
              "attributes": {},
              "value": ["D", "e0", "k", "t", "P"]
            },
            {
              "type": "double",
              "attributes": {},
              "value": [67.2, 37.9, 1.1, 50, 56]
            },
            {
              "type": "character",
              "attributes": {},
              "value": ["Number of deaths", "Life expectancy", "Correction factor", "Time span", "Population size"]
            }
          ]
        },
        {
          "type": "list",
          "attributes": {
            "names": {
              "type": "character",
              "attributes": {},
              "value": ["method", "value", "description"]
            },
            "class": {
              "type": "character",
              "attributes": {},
              "value": ["data.frame"]
            },
            "row.names": {
              "type": "integer",
              "attributes": {},
              "value": [1, 2, 3, 4, 5]
            }
          },
          "value": [
            {
              "type": "character",
              "attributes": {},
              "value": ["D", "e0", "k", "t", "P"]
            },
            {
              "type": "double",
              "attributes": {},
              "value": [74.8, 34.7, 1.1, 50, 57.2]
            },
            {
              "type": "character",
              "attributes": {},
              "value": ["Number of deaths", "Life expectancy", "Correction factor", "Time span", "Population size"]
            }
          ]
        }
      ]
    }

---

    {
      "type": "list",
      "attributes": {
        "names": {
          "type": "character",
          "attributes": {},
          "value": ["method", "value", "description"]
        },
        "class": {
          "type": "character",
          "attributes": {},
          "value": ["data.frame"]
        },
        "row.names": {
          "type": "integer",
          "attributes": {},
          "value": [1, 2, 3, 4, 5]
        }
      },
      "value": [
        {
          "type": "character",
          "attributes": {},
          "value": ["D", "e0", "k", "t", "P"]
        },
        {
          "type": "double",
          "attributes": {},
          "value": [111, 32.2, 1.2, 100, 42.9]
        },
        {
          "type": "character",
          "attributes": {},
          "value": ["Number of deaths", "Life expectancy", "Correction factor", "Time span", "Population size"]
        }
      ]
    }