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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def correct_dims(self, var, dims={}, remove=True):
 """Expands the dimensions to match the dims in the variable Parameters var: xarray.Variable The variable to get the data for dims: dict a mapping from dimension to the slices remove: bool If True, dimensions in `dims` that are not in the dimensions of `var` are removed"""

        method_mapping = {'x': self.get_xname,
                          'z': self.get_zname, 't': self.get_tname}
        dims = dict(dims)
        if self.is_unstructured(var):  # we assume a one-dimensional grid
            method_mapping['y'] = self.get_xname
        else:
            method_mapping['y'] = self.get_yname
        for key in six.iterkeys(dims.copy()):
            if key in method_mapping and key not in var.dims:
                dim_name = method_mapping[key](var, self.ds.coords)
                if dim_name in dims:
                    dims.pop(key)
                else:
                    new_name = method_mapping[key](var)
                    if new_name is not None:
                        dims[new_name] = dims.pop(key)
        # now remove the unnecessary dimensions
        if remove:
            for key in set(dims).difference(var.dims):
                dims.pop(key)
                self.logger.debug(
                    "Could not find a dimensions matching %s in variable %s!",
                    key, var)
        return dims