{
  "__type": "IngestedDoc",
  "__tag": 4010,
  "_content": {
    "Notes": {
      "__type": "Section",
      "__tag": 4015,
      "children": [],
      "title": [],
      "level": 0,
      "target": null
    },
    "Warns": {
      "__type": "Section",
      "__tag": 4015,
      "children": [],
      "title": [],
      "level": 0,
      "target": null
    },
    "Raises": {
      "__type": "Section",
      "__tag": 4015,
      "children": [],
      "title": [],
      "level": 0,
      "target": null
    },
    "Yields": {
      "__type": "Section",
      "__tag": 4015,
      "children": [],
      "title": [],
      "level": 0,
      "target": null
    },
    "Methods": {
      "__type": "Section",
      "__tag": 4015,
      "children": [],
      "title": [],
      "level": 0,
      "target": null
    },
    "Returns": {
      "__type": "Section",
      "__tag": 4015,
      "children": [],
      "title": [],
      "level": 0,
      "target": null
    },
    "Summary": {
      "__type": "Section",
      "__tag": 4015,
      "children": [
        {
          "__type": "Paragraph",
          "__tag": 4045,
          "children": [
            {
              "__type": "Text",
              "__tag": 4046,
              "value": "Diff two "
            },
            {
              "__type": "CrossRef",
              "__tag": 4002,
              "value": "Header",
              "reference": {
                "__type": "LocalRef",
                "__tag": 4022,
                "kind": "module",
                "path": "astropy.io.fits.header:Header"
              },
              "kind": "module"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": " objects."
            }
          ]
        }
      ],
      "title": [],
      "level": 0,
      "target": null
    },
    "Receives": {
      "__type": "Section",
      "__tag": 4015,
      "children": [],
      "title": [],
      "level": 0,
      "target": null
    },
    "Warnings": {
      "__type": "Section",
      "__tag": 4015,
      "children": [],
      "title": [],
      "level": 0,
      "target": null
    },
    "Attributes": {
      "__type": "Section",
      "__tag": 4015,
      "children": [],
      "title": [],
      "level": 0,
      "target": null
    },
    "Parameters": {
      "__type": "Section",
      "__tag": 4015,
      "children": [],
      "title": [],
      "level": 0,
      "target": null
    },
    "Extended Summary": {
      "__type": "Section",
      "__tag": 4015,
      "children": [
        {
          "__type": "Paragraph",
          "__tag": 4045,
          "children": [
            {
              "__type": "CrossRef",
              "__tag": 4002,
              "value": "HeaderDiff",
              "reference": {
                "__type": "LocalRef",
                "__tag": 4022,
                "kind": "module",
                "path": "astropy.io.fits.diff:HeaderDiff"
              },
              "kind": "module"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": " objects have the following diff attributes:"
            }
          ]
        },
        {
          "__type": "BulletList",
          "__tag": 4053,
          "ordered": false,
          "start": 1,
          "children": [
            {
              "__type": "ListItem",
              "__tag": 4054,
              "children": [
                {
                  "__type": "Paragraph",
                  "__tag": 4045,
                  "children": [
                    {
                      "__type": "InlineCode",
                      "__tag": 4051,
                      "value": "diff_keyword_count"
                    },
                    {
                      "__type": "Text",
                      "__tag": 4046,
                      "value": ": If the two headers contain a different number of   keywords, this contains a 2-tuple of the keyword count for each header."
                    }
                  ]
                }
              ]
            },
            {
              "__type": "ListItem",
              "__tag": 4054,
              "children": [
                {
                  "__type": "Paragraph",
                  "__tag": 4045,
                  "children": [
                    {
                      "__type": "InlineCode",
                      "__tag": 4051,
                      "value": "diff_keywords"
                    },
                    {
                      "__type": "Text",
                      "__tag": 4046,
                      "value": ": If either header contains one or more keywords that   don't appear at all in the other header, this contains a 2-tuple   consisting of a list of the keywords only appearing in header a, and a   list of the keywords only appearing in header b."
                    }
                  ]
                }
              ]
            },
            {
              "__type": "ListItem",
              "__tag": 4054,
              "children": [
                {
                  "__type": "Paragraph",
                  "__tag": 4045,
                  "children": [
                    {
                      "__type": "InlineCode",
                      "__tag": 4051,
                      "value": "diff_duplicate_keywords"
                    },
                    {
                      "__type": "Text",
                      "__tag": 4046,
                      "value": ": If a keyword appears in both headers at   least once, but contains a different number of duplicates (for example, a   different number of HISTORY cards in each header), an item is added to   this dict with the keyword as the key, and a 2-tuple of the different   counts of that keyword as the value.  For example        "
                    }
                  ]
                },
                {
                  "__type": "Code",
                  "__tag": 4050,
                  "value": "{'HISTORY': (20, 19)}",
                  "execution_status": null,
                  "out": ""
                },
                {
                  "__type": "Paragraph",
                  "__tag": 4045,
                  "children": [
                    {
                      "__type": "Text",
                      "__tag": 4046,
                      "value": "means that header a contains 20 HISTORY cards, while header b contains   only 19 HISTORY cards."
                    }
                  ]
                }
              ]
            },
            {
              "__type": "ListItem",
              "__tag": 4054,
              "children": [
                {
                  "__type": "Paragraph",
                  "__tag": 4045,
                  "children": [
                    {
                      "__type": "InlineCode",
                      "__tag": 4051,
                      "value": "diff_keyword_values"
                    },
                    {
                      "__type": "Text",
                      "__tag": 4046,
                      "value": ": If any of the common keyword between the two   headers have different values, they appear in this dict.  It has a   structure similar to "
                    },
                    {
                      "__type": "InlineCode",
                      "__tag": 4051,
                      "value": "diff_duplicate_keywords"
                    },
                    {
                      "__type": "Text",
                      "__tag": 4046,
                      "value": ", with the keyword as the   key, and a 2-tuple of the different values as the value.  For example        "
                    }
                  ]
                },
                {
                  "__type": "Code",
                  "__tag": 4050,
                  "value": "{'NAXIS': (2, 3)}",
                  "execution_status": null,
                  "out": ""
                },
                {
                  "__type": "Paragraph",
                  "__tag": 4045,
                  "children": [
                    {
                      "__type": "Text",
                      "__tag": 4046,
                      "value": "means that the NAXIS keyword has a value of 2 in header a, and a value of   3 in header b.  This excludes any keywords matched by the   "
                    },
                    {
                      "__type": "InlineCode",
                      "__tag": 4051,
                      "value": "ignore_keywords"
                    },
                    {
                      "__type": "Text",
                      "__tag": 4046,
                      "value": " list."
                    }
                  ]
                }
              ]
            },
            {
              "__type": "ListItem",
              "__tag": 4054,
              "children": [
                {
                  "__type": "Paragraph",
                  "__tag": 4045,
                  "children": [
                    {
                      "__type": "InlineCode",
                      "__tag": 4051,
                      "value": "diff_keyword_comments"
                    },
                    {
                      "__type": "Text",
                      "__tag": 4046,
                      "value": ": Like "
                    },
                    {
                      "__type": "InlineCode",
                      "__tag": 4051,
                      "value": "diff_keyword_values"
                    },
                    {
                      "__type": "Text",
                      "__tag": 4046,
                      "value": ", but contains   differences between keyword comments."
                    }
                  ]
                }
              ]
            }
          ]
        },
        {
          "__type": "Paragraph",
          "__tag": 4045,
          "children": [
            {
              "__type": "CrossRef",
              "__tag": 4002,
              "value": "HeaderDiff",
              "reference": {
                "__type": "LocalRef",
                "__tag": 4022,
                "kind": "module",
                "path": "astropy.io.fits.diff:HeaderDiff"
              },
              "kind": "module"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": " objects also have a "
            },
            {
              "__type": "InlineCode",
              "__tag": 4051,
              "value": "common_keywords"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": " attribute that lists all keywords that appear in both headers."
            }
          ]
        }
      ],
      "title": [],
      "level": 0,
      "target": null
    },
    "Other Parameters": {
      "__type": "Section",
      "__tag": 4015,
      "children": [],
      "title": [],
      "level": 0,
      "target": null
    }
  },
  "_ordered_sections": [
    "Summary",
    "Extended Summary",
    "Parameters",
    "Attributes",
    "Methods",
    "Returns",
    "Yields",
    "Receives",
    "Other Parameters",
    "Raises",
    "Warns",
    "Warnings",
    "Notes"
  ],
  "item_file": "/astropy/io/fits/diff.py",
  "item_line": 657,
  "item_type": "class",
  "aliases": [
    "astropy.io.fits.HeaderDiff"
  ],
  "example_section_data": {
    "__type": "Section",
    "__tag": 4015,
    "children": [],
    "title": [],
    "level": 0,
    "target": null
  },
  "see_also": [],
  "signature": {
    "__type": "SignatureNode",
    "__tag": 4029,
    "kind": "function",
    "parameters": [
      {
        "__type": "SigParam",
        "__tag": 4030,
        "name": "a",
        "annotation": {
          "__type": "Empty",
          "__tag": 4031
        },
        "kind": "POSITIONAL_OR_KEYWORD",
        "default": {
          "__type": "Empty",
          "__tag": 4031
        }
      },
      {
        "__type": "SigParam",
        "__tag": 4030,
        "name": "b",
        "annotation": {
          "__type": "Empty",
          "__tag": 4031
        },
        "kind": "POSITIONAL_OR_KEYWORD",
        "default": {
          "__type": "Empty",
          "__tag": 4031
        }
      },
      {
        "__type": "SigParam",
        "__tag": 4030,
        "name": "ignore_keywords",
        "annotation": {
          "__type": "Empty",
          "__tag": 4031
        },
        "kind": "POSITIONAL_OR_KEYWORD",
        "default": "[]"
      },
      {
        "__type": "SigParam",
        "__tag": 4030,
        "name": "ignore_comments",
        "annotation": {
          "__type": "Empty",
          "__tag": 4031
        },
        "kind": "POSITIONAL_OR_KEYWORD",
        "default": "[]"
      },
      {
        "__type": "SigParam",
        "__tag": 4030,
        "name": "rtol",
        "annotation": {
          "__type": "Empty",
          "__tag": 4031
        },
        "kind": "POSITIONAL_OR_KEYWORD",
        "default": "0.0"
      },
      {
        "__type": "SigParam",
        "__tag": 4030,
        "name": "atol",
        "annotation": {
          "__type": "Empty",
          "__tag": 4031
        },
        "kind": "POSITIONAL_OR_KEYWORD",
        "default": "0.0"
      },
      {
        "__type": "SigParam",
        "__tag": 4030,
        "name": "ignore_blanks",
        "annotation": {
          "__type": "Empty",
          "__tag": 4031
        },
        "kind": "POSITIONAL_OR_KEYWORD",
        "default": "True"
      },
      {
        "__type": "SigParam",
        "__tag": 4030,
        "name": "ignore_blank_cards",
        "annotation": {
          "__type": "Empty",
          "__tag": 4031
        },
        "kind": "POSITIONAL_OR_KEYWORD",
        "default": "True"
      }
    ],
    "return_annotation": {
      "__type": "Empty",
      "__tag": 4031
    },
    "target_name": "HeaderDiff"
  },
  "references": null,
  "qa": "astropy.io.fits.diff:HeaderDiff",
  "arbitrary": [],
  "local_refs": []
}