add my.body.sleep, combine together emfit/jawbone

my/body/sleep/common.py

@@ -0,0 +1,17 @@
+from ...core import stat, Stats
+from ...core.pandas import DataFrameT, check_dataframe as cdf
+
+
+class Combine:
+    def __init__(self, modules) -> None:
+        self.modules = modules
+
+    @cdf
+    def dataframe(self) -> DataFrameT:
+        import pandas as pd # type: ignore
+        # todo include 'source'?
+        df = pd.concat([m.dataframe() for m in self.modules])
+        return df
+
+    def stats(self) -> Stats:
+        return stat(self.dataframe)