diff --git a/python/obitools3/__init__.pyc b/python/obitools3/__init__.pyc
new file mode 100644
index 0000000..418f2f1
Binary files /dev/null and b/python/obitools3/__init__.pyc differ
diff --git a/python/obitools3/obidms/_obidms.c b/python/obitools3/obidms/_obidms.c
new file mode 100644
index 0000000..06f2230
--- /dev/null
+++ b/python/obitools3/obidms/_obidms.c
@@ -0,0 +1 @@
+#error Do not use this file, it is the result of a failed Cython compilation.
diff --git a/python/obitools3/obidms/capi/obidms.pxd b/python/obitools3/obidms/capi/obidms.pxd
new file mode 100644
index 0000000..5b922eb
--- /dev/null
+++ b/python/obitools3/obidms/capi/obidms.pxd
@@ -0,0 +1,8 @@
+cdef extern from "obidms.h" nogil:
+    struct OBIDMS_t:
+        pass
+
+    ctypedef OBIDMS_t* OBIDMS_p 
+
+    OBIDMS_p obi_dms(const_char_p dms_name)
+    int obi_close_dms(OBIDMS_p dms)
diff --git a/python/obitools3/obidms/capi/obidmscolumn.pxd b/python/obitools3/obidms/capi/obidmscolumn.pxd
new file mode 100644
index 0000000..1492402
--- /dev/null
+++ b/python/obitools3/obidms/capi/obidmscolumn.pxd
@@ -0,0 +1,19 @@
+cdef extern from "obidmscolumn.h" nogil:
+    struct OBIDMS_column_t:
+        pass
+
+    ctypedef OBIDMS_column_t* OBIDMS_column_p
+
+    OBIDMS_column_p obi_create_column(OBIDMS_p dms, const char* column_name, OBIType_t type, size_t nb_lines, size_t nb_elements_per_line, const char* elements_names)
+    size_t obi_column_get_nb_lines_used(OBIDMS_column_p column)
+    const char* obi_column_get_elements_names(OBIDMS_column_p column)
+    void obi_column_make_unwritable(OBIDMS_column_p column)
+    OBIDMS_column_p obi_open_column(OBIDMS_p dms, const char* column_name, obiversion_t version_number)
+    OBIType_t obi_column_get_type(OBIDMS_column_p column)
+    int obi_close_column(OBIDMS_column_p column)
+    OBIType_t obi_column_get_data_type_from_name(OBIDMS_p dms, const char* column_name)
+    OBIDMS_column_p obi_clone_column(OBIDMS_p dms, const char* column_name, obiversion_t version_number, bint clone_data)
+    int obi_truncate_and_close_column(OBIDMS_column_p column)
+    obiversion_t obi_column_get_latest_version_from_name(OBIDMS_p dms, const char* column_name)
+    OBIType_t obi_column_get_data_type_from_name(OBIDMS_p dms, const char* column_name)
+    size_t obi_column_get_line_count_from_name(OBIDMS_p dms, const char* column_name)
diff --git a/python/obitools3/obidms/capi/obierrno.pxd b/python/obitools3/obidms/capi/obierrno.pxd
new file mode 100644
index 0000000..186d945
--- /dev/null
+++ b/python/obitools3/obidms/capi/obierrno.pxd
@@ -0,0 +1,3 @@
+cdef extern from "obierrno.h" nogil:
+    extern int obi_errno
+
diff --git a/python/obitools3/obidms/capi/obitypes.pxd b/python/obitools3/obidms/capi/obitypes.pxd
new file mode 100644
index 0000000..cd3a75e
--- /dev/null
+++ b/python/obitools3/obidms/capi/obitypes.pxd
@@ -0,0 +1,33 @@
+from libc.stdint cimport int32_t
+
+
+cdef extern from *:
+    ctypedef char* const_char_p "const char*"
+
+cdef extern from "obidmscolumn.h" nogil:
+
+    ctypedef int32_t obiversion_t
+
+cdef extern from "obitypes.h" nogil:
+
+    enum OBIType:       # TODO je sais pas si ça sert de declarer le contenu de l'enum
+        OBI_VOID = 0,
+        OBI_INT,
+        OBI_FLOAT,
+        OBI_BOOL,
+        OBI_CHAR,
+        OBI_IDX
+    
+    ctypedef OBIType OBIType_t
+
+
+    enum OBIBool:
+        pass
+    
+    ctypedef OBIBool obibool_t
+    ctypedef int32_t obiint_t
+    ctypedef double obifloat_t
+    ctypedef char obichar_t  
+    ctypedef size_t obiidx_t
+
+    char* name_data_type(int data_type)
diff --git a/python/obitools3/utils.pxd b/python/obitools3/utils.pxd
new file mode 100644
index 0000000..b37e77a
--- /dev/null
+++ b/python/obitools3/utils.pxd
@@ -0,0 +1,3 @@
+cdef bytes str2bytes(str string)
+
+cdef str bytes2str(bytes string)
\ No newline at end of file
diff --git a/python/obitools3/utils.pyx b/python/obitools3/utils.pyx
new file mode 100644
index 0000000..0d22078
--- /dev/null
+++ b/python/obitools3/utils.pyx
@@ -0,0 +1,5 @@
+cdef bytes str2bytes(str string):
+    return string.encode('ascii')
+
+cdef str bytes2str(bytes string):
+    return string.decode('ascii')
\ No newline at end of file
diff --git a/python/obitools3/version.pyc b/python/obitools3/version.pyc
new file mode 100644
index 0000000..0773059
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