parameters: (self, environment, template)
docstring: Get the template source, filename and reload helper for a template.
          It's passed the environment and template name and has to return a
          tuple in the form ``(source, filename, uptodate)`` or raise a
          `TemplateNotFound` error if it can't locate the template.
  
          The source part of the returned tuple must be the source of the
          template as unicode string or a ASCII bytestring.  The filename should
          be the name of the file on the filesystem if it was loaded from there,
          otherwise `None`.  The filename is used by python for the tracebacks
          if no loader extension is used.
  
          The last item in the tuple is the `uptodate` function.  If auto
          reloading is enabled it's always called to check if the template
          changed.  No arguments are passed so the function must store the
          old state somewhere (for example in a closure).  If it returns `False`
          the template will be reloaded.
docstring_summary: Get the template source, filename and reload helper for a template.
          It's passed the environment and template name and has to return a
          tuple in the form ``(source, filename, uptodate)`` or raise a
          `TemplateNotFound` error if it can't locate the template.
docstring_tokens: Get the template source filename and reload helper for a template . It s passed the environment and template name and has to return a tuple in the form ( source filename uptodate ) or raise a TemplateNotFound error if it can t locate the template .
function: def get_source(self, environment, template):
          """Get the template source, filename and reload helper for a template.
          It's passed the environment and template name and has to return a
          tuple in the form ``(source, filename, uptodate)`` or raise a
          `TemplateNotFound` error if it can't locate the template.
  
          The source part of the returned tuple must be the source of the
          template as unicode string or a ASCII bytestring.  The filename should
          be the name of the file on the filesystem if it was loaded from there,
          otherwise `None`.  The filename is used by python for the tracebacks
          if no loader extension is used.
  
          The last item in the tuple is the `uptodate` function.  If auto
          reloading is enabled it's always called to check if the template
          changed.  No arguments are passed so the function must store the
          old state somewhere (for example in a closure).  If it returns `False`
          the template will be reloaded.
          """
          if not self.has_source_access:
              raise RuntimeError('%s cannot provide access to the source' %
                                 self.__class__.__name__)
          raise TemplateNotFound(template)
function_tokens: def get_source ( self , environment , template ) : if not self . has_source_access : raise RuntimeError ( '%s cannot provide access to the source' % self . __class__ . __name__ ) raise TemplateNotFound ( template )