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1 """ |
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2 Implements the tree containing pages and their metadata |
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3 """ |
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4 |
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5 import tree_parse |
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6 |
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7 # path to file containing the page metadata tree |
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8 PAGE_TREE_FILE = "pages/list" |
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9 |
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10 |
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11 class PageInfo (object) : |
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12 """ |
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13 Contains metainformation about a page |
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14 """ |
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15 |
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16 def __init__ (self, parent, name, title, children=None) : |
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17 """ |
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18 Initialize, children defaults to empty list |
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19 """ |
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20 |
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21 # store |
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22 self.parent = parent |
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23 self.name = name |
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24 self.title = title |
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25 self.children = children if children else [] |
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26 |
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27 # no url get |
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28 self._url = None |
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29 |
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30 def set_parent (self, parent) : |
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31 """ |
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32 Set a parent where non was set before |
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33 """ |
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34 |
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35 assert self.parent is None |
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36 |
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37 self.parent = parent |
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38 |
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39 def add_child (self, child) : |
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40 """ |
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41 Add a PageInfo child |
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42 """ |
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43 |
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44 self.children.append(child) |
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45 |
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46 def get_child (self, name) : |
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47 """ |
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48 Look up a child by name, returning None if not found |
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49 """ |
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50 |
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51 return dict((c.name, c) for c in self.children).get(name) |
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52 |
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53 def get_ancestry (self) : |
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54 """ |
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55 Returns a list of this page's parents and the page itself, but not root |
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56 """ |
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57 |
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58 # collect in reverse order |
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59 ancestry = [] |
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60 |
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61 # starting from self |
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62 item = self |
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63 |
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64 # add all items, but not root |
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65 while item and item.parent : |
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66 ancestry.append(item) |
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67 |
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68 item = item.parent |
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69 |
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70 # reverse |
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71 ancestry.reverse() |
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72 |
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73 # done |
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74 return ancestry |
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75 |
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76 @property |
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77 def url (self) : |
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78 """ |
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79 Build this page's URL |
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80 """ |
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81 |
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82 # cached? |
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83 if self._url : |
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84 return self._url |
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85 |
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86 segments = [item.name for item in self.get_ancestry()] |
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87 |
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88 # add empty segment if dir |
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89 if self.children : |
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90 segments.append('') |
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91 |
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92 # join |
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93 url = '/'.join(segments) |
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94 |
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95 # cache |
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96 self._url = url |
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97 |
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98 # done |
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99 return url |
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100 |
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101 class PageTree (object) : |
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102 """ |
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103 The tree of pages, rooted at .root. |
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104 |
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105 Use load_page_tree to initialize the global page_tree instance, and then use that |
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106 """ |
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107 |
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108 def __init__ (self) : |
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109 """ |
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110 Empty PageList, must call load_page_list to initialize, once |
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111 """ |
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112 |
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113 def _load (self, path) : |
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114 """ |
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115 Processes the lines in the given file |
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116 """ |
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117 |
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118 # parse tree |
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119 tree = tree_parse.parse(path, ':') |
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120 |
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121 def _create_node (parent, item) : |
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122 """ |
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123 Creates and returns a PageInfo from the given parent node and (line_number, line, children) tuple item |
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124 """ |
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125 |
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126 # unpack |
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127 line_number, line, children = item |
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128 |
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129 # parse line |
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130 url, title = line.split(':') |
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131 |
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132 # remove whitespace |
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133 url = url.strip() |
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134 title = title.strip() |
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135 |
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136 # create PageInfo |
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137 node = PageInfo(parent, url, title) |
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138 |
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139 # set node children |
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140 node.children = [ |
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141 _create_node(node, child_item) for child_item in children |
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142 ] |
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143 |
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144 # return |
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145 return node |
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146 |
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147 # translate |
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148 self.root = _create_node(None, tree) |
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149 |
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150 # *evil cackle* |
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151 self.root.children.insert(0, self.root) |
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152 |
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153 def get_page (self, url) : |
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154 """ |
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155 Lookup the given page URL, and return the matching PageInfo object, or None, if not found |
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156 """ |
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157 |
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158 # start from root |
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159 node = self.root |
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160 |
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161 # traverse the object tree |
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162 for segment in url.split('/') : |
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163 if segment : |
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164 node = node.get_child(segment) |
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165 |
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166 if not node : |
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167 return None |
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168 |
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169 # return |
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170 return node |
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171 |
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172 def get_siblings (self, url) : |
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173 """ |
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174 Get the list of siblings for the given url, including the given page itself |
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175 """ |
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176 |
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177 # look up the page itself |
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178 page = self.get_page(url) |
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179 |
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180 # specialcase root/unknown node |
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181 if page and page.parent : |
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182 return page.parent.children |
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183 |
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184 else : |
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185 return self.root.children |
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186 |
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187 def dump (self) : |
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188 """ |
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189 Returns a string representation of the tree |
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190 """ |
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191 |
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192 def _print_node (indent, node) : |
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193 return '\n'.join('%s%s' % (' '*indent, line) for line in [ |
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194 "%-15s : %s" % (node.name, node.title) |
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195 ] + [ |
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196 _print_node(indent + 4, child) for child in node.children if child != node |
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197 ]) |
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198 |
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199 return _print_node(0, self.root) |
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200 |
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201 # global singleton PageList instance |
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202 page_tree = PageTree() |
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203 |
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204 def load () : |
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205 """ |
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206 Load the global singleton PageInfo instance |
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207 """ |
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208 |
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209 page_tree._load(PAGE_TREE_FILE) |
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210 |